Commit author for suggestions is note author

Git differentiates the author and committer so that the person who
writes the change can be acknowledged even though someone else committed
it. Suggestions may be proposed by a different person to who applies the
change. If this information is lost, the provenance of the change can be
hard to discern.

app/services/suggestions/apply_service.rb

@@ -36,12 +36,18 @@ module Suggestions
         .track_apply_suggestion_action(user: current_user)
     end
 
+    def author
+      Gitlab::Git::User.from_gitlab(suggestion_set.authors.first) if suggestion_set.authors.one?
+    end
+
     def multi_service
       params = {
         commit_message: commit_message,
         branch_name: suggestion_set.branch,
         start_branch: suggestion_set.branch,
-        actions: suggestion_set.actions
+        actions: suggestion_set.actions,
+        author_name: author&.name,
+        author_email: author&.email
       }
 
       ::Files::MultiService.new(suggestion_set.project, current_user, params)

lib/gitlab/suggestions/suggestion_set.rb

@@ -39,6 +39,10 @@ module Gitlab
         @file_paths ||= suggestions.map(&:file_path).uniq
       end
 
+      def authors
+        suggestions.map { |suggestion| suggestion.note.author }.uniq
+      end
+
       private
 
       def first_suggestion