Reword messages for PR auto merging (#2117)

conf/locale/locale_en-US.ini

@@ -510,9 +510,9 @@ pulls.merged = Merged
 pulls.has_merged = This pull request has been merged successfully!
 pulls.data_broken = Data of this pull request has been broken due to deletion of fork information.
 pulls.is_checking = The conflict checking is still in progress, please refresh page in few moments.
-pulls.can_auto_merge_desc = You can perform auto-merge operation on this pull request.
+pulls.can_auto_merge_desc = This pull request can be merged automatically.
-pulls.cannot_auto_merge_desc = You can't perform auto-merge operation because there are conflicts between commits.
+pulls.cannot_auto_merge_desc = This pull request can't be merged automatically because there are conflicts.
-pulls.cannot_auto_merge_helper = Please use command line tool to solve it.
+pulls.cannot_auto_merge_helper = Please merge manually in order to resolve the conflicts.
 pulls.merge_pull_request = Merge Pull Request
 pulls.open_unmerged_pull_exists = `You can't perform reopen operation because there is already an open pull request (#%d) from same repository with same merge information and is waiting for merging.`