Background:
This issue is part of the meta-issue for updating the hook_help texts of the Drupal 8 modules:
#1908570: [meta] Update or create hook_help() texts for D8 core modules
Tasks:
a) [DONE - patch ready] review / write the hook_help text according to help guidelines http://drupal.org/node/632280
More details are on the meta-issue.
b) (novice) Final manual testing:
1. Apply the patch.
2. Go to admin/help.
3. Click on the help page for this module (Language).
4. Verify that the help page is OK:
- Verify that all the links work
- Verify that all mentions of pages/text/permissions within the UI match what is seen in the UI
- Verify that the formatting is OK.