docs: fix headers hierarchy in mount docs

Author: darkdragon-001

docs/content/commands/rclone_mount.md

@@ -336,7 +336,7 @@ full new copy of the file.
 When mounting with `--read-only`, attempts to write to files will fail *silently*
 as opposed to with a clear warning as in macFUSE.
 
-# Mounting on Linux
+## Mounting on Linux
 
 On newer versions of Ubuntu, you may encounter the following error when running
 `rclone mount`: