Fix reply on code review (#10227)

Co-authored-by: zeripath <art27@cantab.net>

templates/repo/diff/comment_form.tmpl

 			<span class="markdown-info">{{svg "octicon-markdown" 16}} {{$.root.i18n.Tr "repo.diff.comment.markdown_info"}}</span>
 			<div class="ui right floated">
 				{{if $.reply}}
-					<button name="reply" value="{{$.reply}}" class="ui submit green tiny button btn-reply">{{$.root.i18n.Tr "repo.diff.comment.reply"}}</button>
+					<input type="hidden" name="reply" value="{{$.reply}}">
+					<button class="ui submit green tiny button btn-reply" onclick="window.submitReply(this);">{{$.root.i18n.Tr "repo.diff.comment.reply"}}</button>
 				{{else}}
 					{{if $.root.CurrentReview}}
 						<button name="is_review" value="true" type="submit"

web_src/js/index.js

     form.closest('.comment-code-cloud').remove();
   }
 };
+
+window.submitReply = function (btn) {
+  const form = $(btn).closest('form');
+  if (form.length > 0 && form.hasClass('comment-form')) {
+    form.submit();
+  }
+};
+
 window.onOAuthLoginClick = function () {
   const oauthLoader = $('#oauth2-login-loader');
   const oauthNav = $('#oauth2-login-navigator');