Add localization docs (#11411)

* Add localization docs

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Clarify bleeding edge vs release

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Capitalize Crowdin

Signed-off-by: jolheiser <john.olheiser@gmail.com>

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

docs/content/doc/features/localization.en-us.md

@@ -15,4 +15,17 @@ menu:
 
 # Localization
 
-## TBD
+Gitea's localization happens through our [Crowdin project](https://crowdin.com/project/gitea).
+
+For changes to an **English** translation, a pull request can be made that changes the appropriate key in 
+the [english locale](https://github.com/go-gitea/gitea/blob/master/options/locale/locale_en-US.ini).
+
+For changes to a **non-English** translation, refer to the Crowdin project above.
+
+## Supported Languages
+
+Any language listed in the above Crowdin project will be supported as long as 25% or more has been translated.
+
+After a translation has been accepted, it will be reflected in the main repository after the next Crowdin sync, which is generally after any PR is merged.  
+At the time of writing, this means that a changed translation may not appear until the following Gitea release.  
+If you use a bleeding edge build, it should appear as soon as you update after the change is synced.