Merge branch 'api-alphabetical' into 'master'

Keep API mounts in alphabetical order

## What does this MR do?

Just a cosmetic change to keep the API mounts in order.

See merge request !6515

lib/api/api.rb

@@ -28,6 +28,7 @@ module API
     helpers ::SentryHelper
     helpers ::API::Helpers
 
+    # Keep in alphabetical order
     mount ::API::AccessRequests
     mount ::API::AwardEmoji
     mount ::API::Branches
@@ -48,6 +49,7 @@ module API
     mount ::API::Lint
     mount ::API::Members
     mount ::API::MergeRequests
+    mount ::API::MergeRequestDiffs
     mount ::API::Milestones
     mount ::API::Namespaces
     mount ::API::Notes
@@ -70,6 +72,5 @@ module API
     mount ::API::Triggers
     mount ::API::Users
     mount ::API::Variables
-    mount ::API::MergeRequestDiffs
   end
 end