Changes related to the translation pages

The following commit/PR attempts to do minor tweaks and improvements over all the translation-related content:
 - Renamed the page titles on the index bar to be more clear.
 - Edited the new-translations.md page in order to dissuade people from directly editing the msg_hash_XX.h files (since Crowdin will automatically overwrite the contents and any translations added via push/PR could require finetuning by existing translators), as well as changing its purpose to teach how to add a new language.
 - Fixing a missing line-jump in new-translations-crowdin.md.
 - Re-cut the button icons so they are more proportionate to the texts.
 - Edited every screenshot that contained the LanguageTool icon (so people don't ask why is that thing not in their browsers, sorry about that) to remove them.
 - Did a PNG optimization pass to the entire folder. The PNG sizes have been halved.

docs/development/retroarch/new-translations-crowdin.md

@@ -69,6 +69,7 @@ Click on any string to see them in the middle area. The **Source String** (the o
 In the very few cases where the source string can be kept as-is, you can click the ‘**Copy Source**’ button ![Copy Source](../../image/development/crowdin-copy-source.png) to do so.
 
 In the string list (on the left side of the screen) some strings have a balloon icon ![Comments icon](../../image/development/crowdin-comments-icon.png). This icon shows that the string has comments written by other translators and developers. Comments may include interesting and/or important information that could help you decide on how best to translate a specific string. You can also write comments in case you have questions or additional information regarding any particular string.
+
 Please make sure that any comment you write is in __English__, as that is the official project language and the comments are visible to _everyone_. Comments will be displayed at Crowdin’s right column. In case there are no comments being displayed there, make sure that the left-most button of that column is active.
 
 <figure markdown>

docs/development/retroarch/new-translations.md

@@ -1,6 +1,6 @@
-# Adding a translation to a new language
+# Adding a new language to RetroArch
 
-## Files you need to change
+## Files to change
 
 * `libretro-common/include/libretro.h`
 * `msg_hash.h`
@@ -96,21 +96,30 @@
 * Be careful when creating and editing your new translation files as some text
   editors do strip the BOM without warning.
 
-### Translation
-
-If you speak the target language xx then you could start translating literals in
-
-* `intl/msg_hash_xx.c`
-* `intl/msg_hash_xx.h`
-
-by replacing the English original ones with its translations.
-
 ### Example: Addition of Arabic language:
 
 * Commit [45580cb](https://github.com/libretro/RetroArch/commit/45580cb9a8f0fcd0a87f00eadf26d87f05289485)
 * Commit [d8f1a08](https://github.com/libretro/RetroArch/commit/d8f1a08a4758851d5530d311303146257cbf8216)
 * Commit [7a0428f](https://github.com/libretro/RetroArch/commit/7a0428fc769fd0eca663207134bec311aa3e30f3)
 
+### Translation
+
+If you speak the target language xx then you could start translating literals in
+
+* `intl/msg_hash_xx.c`
+
+by replacing the English original one with its translations.
+
+The main file for RetroArch is located here:
+
+* `intl/msg_hash_xx.h`
+
+But .h files are periodically updated and overwritten by the Crowdin translations website 
+([Link here](https://crowdin.com/project/retroarch), so it's best to do any changes to 
+non-English languages there. If you want to know more, go to the 
+([Helping with RetroArch translations](https://docs.libretro.com/development/retroarch/new-translations-crowdin/)
+doc.
+
 ## See also
 
 * [Adding a RetroArch menu option](new-menu-options.md)

mkdocs.yml

@@ -303,8 +303,8 @@ nav:
         - 'Input Driver Specification': 'development/retroarch/input/input-drivers.md'
         - 'Input Overlays': 'development/retroarch/input/overlay.md'
         - 'Parallel Port Controllers': 'development/retroarch/input/parallel-port-controllers.md'
-      - 'Adding Translations(not active)': 'development/retroarch/new-translations.md'
-      - 'Adding Translations with Crowdin': 'development/retroarch/new-translations-crowdin.md'
+      - 'Adding New Languages or New Strings': 'development/retroarch/new-translations.md'
+      - 'Helping with RetroArch translations': 'development/retroarch/new-translations-crowdin.md'
       - 'Network Protocols':
         - 'Netplay': 'development/retroarch/netplay.md'
         - 'Network Control Interface': 'development/retroarch/network-control-interface.md'