change text, add animation

Author: wxiaoguang

options/locale/locale_en-US.ini

@@ -1880,7 +1880,7 @@ pulls.add_prefix = Add <strong>%s</strong> prefix
 pulls.remove_prefix = Remove <strong>%s</strong> prefix
 pulls.data_broken = This pull request is broken due to missing fork information.
 pulls.files_conflicted = This pull request has changes conflicting with the target branch.
-pulls.is_checking = "Merge conflict checking is in progress. Try again in few moments."
+pulls.is_checking = Checking for merge conflicts ...
 pulls.is_ancestor = "This branch is already included in the target branch. There is nothing to merge."
 pulls.is_empty = "The changes on this branch are already on the target branch. This will be an empty commit."
 pulls.required_status_check_failed = Some required checks were not successful.

templates/repo/issue/view_content/pull_merge_box.tmpl

@@ -103,7 +103,7 @@
 				{{template "repo/issue/view_content/update_branch_by_merge" $}}
 			{{else if .Issue.PullRequest.IsChecking}}
 				<div class="item">
-					{{svg "octicon-sync"}}
+					{{svg "octicon-sync" 16 "circular-spin"}}
 					{{ctx.Locale.Tr "repo.pulls.is_checking"}}
 				</div>
 			{{else if .Issue.PullRequest.IsAncestor}}