Translate docs with po4a (#2590)

* [i18n] Add docs po4a script

* Add proof of concept

* Add a few more translations

* Hush ShellCheck and shfmt

* Make that list po4a-friendly

* drat, this document could've probably been auto-generated

* Definitive proof that it's translated from French ;-)

* Add some brand spanking new French translation

* More translation

* Mostly finish that config page

* Fix up FAQ

* More contributing

* Dev first steps

* Let's ignore that admin stuff at the very least for now

* Translate release new version, make French the source first and copy all translations

Then replace French with English in the source.

Much quicker than any alternative route.

* And add the English translation

* Minor stylistic leftover from French

* Most of first steps

* Forgot the extensions

* Use po4a 0.56 to get rid of way too many newlines

* Fix up those newlines

* No point linking to Firefox integration anymore from the new user guide

* Start on main view

* A bunch of main view stuff

* More main view

* And some subscriptions before going to bed

* First steps for devs

* More dev first steps

* Incomplete French → English dev/GH translation

Because I need to ask about that mailing list thing

* Fix typo in docs/en/developers/02_Github.md

* Translate & complete devs/github to English

* Fix up most of extensions

* Is that supposed to be a non-breaking space? Let's see

* Match up some users/mobile access

* More users/mobile access

* Add fresh French translation to Fever API

* Fix typo

* Match frontend todo thingies

* Fix a typo

* Some extensions strings

* Remove Fx subscription service from the docs

Cf. https://github.com/FreshRSS/FreshRSS/pull/2606

* Add translation for https://github.com/FreshRSS/FreshRSS/pull/2643

* fix typo as per https://github.com/FreshRSS/FreshRSS/pull/2643#discussion_r345433009

* Add some more French translations

* Update French translation as per @aledeg comment https://github.com/FreshRSS/FreshRSS/pull/2590#discussion_r345465909

* Translate some of the meaningless stuff

* Translate the rest of contributing.md to French

* Fix conflicts

* Translate Docker first steps to French

* Update with change from #2665

* Add @aledeg corrections

* Overlooked a couple @aledeg corrections thanks to GitHub autohide

* Latest @aledeg suggestions

1 files changed, 39 insertions, 38 deletions

diff --git a/docs/en/users/06_Fever_API.md b/docs/en/users/06_Fever_API.md
index b1cf6cb21..5da090872 100644
--- a/docs/en/users/06_Fever_API.md
+++ b/docs/en/users/06_Fever_API.md
@@ -5,51 +5,52 @@ and general aspects of API access.
 
 ## RSS clients
 
-There are many RSS clients existing supporting Fever APIs but they seem to understand the Fever API a bit differently.
-If your favourite client does not work properly with this API, create an issue and we will have a look.
+There are many RSS clients that support the Fever API, but they seem to understand the Fever API a bit differently.
+If your favourite client doesn't work properly with this API, please create an issue and we'll have a look.
 But we can **only** do that for free clients.
 
 ### Usage & Authentication
 
-Before you can start to use this API, you have to enable and setup API access, which is [documented here](https://freshrss.github.io/FreshRSS/en/users/06_Mobile_access.html),
-and then re-set the user’s API password.
+Before you can start using this API, you have to enable and setup API access, which is [documented here](https://freshrss.github.io/FreshRSS/en/users/06_Mobile_access.html),
+and then reset the user’s API password.
 
-Then point your mobile application to the URL of `fever.php` (e.g. `https://freshrss.example.net/api/fever.php`).
+Then point your mobile application to the `fever.php` address (e.g. `https://freshrss.example.net/api/fever.php`).
 
-## Compatibility
+## Compatible clients
 
 Tested with:
 
-- Android
-  - [Readably](https://play.google.com/store/apps/details?id=com.isaiasmatewos.readably) (Closed source)
+* Android
+  * [Readably](https://play.google.com/store/apps/details?id=com.isaiasmatewos.readably) (Closed source)
 
-- iOS
-  - [Fiery Feeds](https://apps.apple.com/app/fiery-feeds-rss-reader/id1158763303) (Closed source)
-  - [Unread](https://apps.apple.com/app/unread-rss-reader/id1252376153) (Commercial)
-  - [Reeder](https://www.reederapp.com/) (Commercial) (Use its Google Reader API / native FreshRSS option when possible)
+* iOS
+  * [Fiery Feeds](https://apps.apple.com/app/fiery-feeds-rss-reader/id1158763303) (Closed source)
+  * [Unread](https://apps.apple.com/app/unread-rss-reader/id1252376153) (Commercial)
+  * [Reeder](https://www.reederapp.com/) (Commercial) (Use its Google Reader API / native FreshRSS option when possible)
 
-- MacOS
-  - [ReadKit](https://apps.apple.com/app/readkit/id588726889) (Commercial)
+* MacOS
+  * [ReadKit](https://apps.apple.com/app/readkit/id588726889) (Commercial)
 
 
 ## Features
 
-Following features are implemented:
+The following features are implemented:
 
-- fetching categories
-- fetching feeds
-- fetching RSS items (new, favorites, unread, by_id, by_feed, by_category, since)
-- fetching favicons
-- setting read marker for item(s)
-- setting starred marker for item(s)
-- setting read marker for feed
-- setting read marker for category
-- supports FreshRSS extensions, which use the `entry_before_display` hook
+* fetching categories
+* fetching feeds
+* fetching RSS items (new, favorites, unread, by_id, by_feed, by_category, since)
+* fetching favicons
+* setting read marker for item(s)
+* setting starred marker for item(s)
+* setting read marker for feed
+* setting read marker for category
+* supports FreshRSS extensions, which use the `entry_before_display` hook
 
-Following features are not supported:
-- **Hot Links** aka **hot** as there is nothing in FreshRSS yet that is similar or could be used to simulate it
+The following features are not supported:
 
-## Testing and error search
+* **Hot Links** aka **hot** as there is nothing in FreshRSS yet that is similar or could be used to simulate it.
+
+## Testing and debugging
 
 If this API does not work as expected in your RSS reader, you can test it manually with a tool like [Postman](https://www.getpostman.com/).
 
@@ -83,25 +84,25 @@ This should give:
 	"last_refreshed_on_time": "1520013061"
 }
 ```
-Perfect, you are authenticated and can now start testing the more advanced features. Therefor change the URL and append the possible API actions to your request parameters. Check the [original Fever documentation](https://feedafever.com/api) for more information.
+Perfect, you're now authenticated and you can start testing the more advanced features. To do so, change the URL and append the possible API actions to your request parameters. Please refer to the [original Fever documentation](https://feedafever.com/api) for more information.
 
 Some basic calls are:
 
-- https://freshrss.example.net/api/fever.php?api&items
-- https://freshrss.example.net/api/fever.php?api&feeds
-- https://freshrss.example.net/api/fever.php?api&groups
-- https://freshrss.example.net/api/fever.php?api&unread_item_ids
-- https://freshrss.example.net/api/fever.php?api&saved_item_ids
-- https://freshrss.example.net/api/fever.php?api&items&since_id=some_id
-- https://freshrss.example.net/api/fever.php?api&items&max_id=some_id
-- https://freshrss.example.net/api/fever.php?api&mark=item&as=read&id=some_id
-- https://freshrss.example.net/api/fever.php?api&mark=item&as=unread&id=some_id
+* https://freshrss.example.net/api/fever.php?api&items
+* https://freshrss.example.net/api/fever.php?api&feeds
+* https://freshrss.example.net/api/fever.php?api&groups
+* https://freshrss.example.net/api/fever.php?api&unread_item_ids
+* https://freshrss.example.net/api/fever.php?api&saved_item_ids
+* https://freshrss.example.net/api/fever.php?api&items&since_id=some_id
+* https://freshrss.example.net/api/fever.php?api&items&max_id=some_id
+* https://freshrss.example.net/api/fever.php?api&mark=item&as=read&id=some_id
+* https://freshrss.example.net/api/fever.php?api&mark=item&as=unread&id=some_id
 
 Replace `some_id` with a real ID from your `freshrss_username_entry` database.
 
 ### Debugging
 
-If nothing helps and your clients still misbehaves, add these lines to the start of `fever.api`:
+If nothing helps and your client is still misbehaving, you can add the following lines to the beginning of the `fever.api` file to determine the cause of the problems:
 
 ```php
 file_put_contents(__DIR__ . '/fever.log', $_SERVER['HTTP_USER_AGENT'] . ': ' . json_encode($_REQUEST) . PHP_EOL, FILE_APPEND);