Merge branch 'hchouraria-fix-autocomplete-merge-request-target-branches' into 'master'

Add prefix to autocomplete path

See merge request gitlab-org/gitlab!65508

app/assets/javascripts/filtered_search/available_dropdown_mappings.js

@@ -204,7 +204,7 @@ export default class AvailableDropdownMappings {
   getMergeRequestTargetBranchesEndpoint() {
     const endpoint = `${
       gon.relative_url_root || ''
-    }/autocomplete/merge_request_target_branches.json`;
+    }/-/autocomplete/merge_request_target_branches.json`;
 
     const params = {
       group_id: this.getGroupId(),