Merge branch 'docs/fix-syntax-highlighting' into 'master'

Fix code block and other minor fixes

See merge request gitlab-org/gitlab-ce!26894

doc/user/profile/account/two_factor_authentication.md

@@ -162,8 +162,7 @@ a new set of recovery codes with SSH.
 1. Run `ssh git@gitlab.example.com 2fa_recovery_codes`.
 1. You are prompted to confirm that you want to generate new codes. Continuing this process invalidates previously saved codes.
 
-    ```
-    bash
+    ```sh
     $ ssh git@gitlab.example.com 2fa_recovery_codes
     Are you sure you want to generate new two-factor recovery codes?
     Any existing recovery codes you saved will be invalidated. (yes/no)