Fix a UI error when folding a file content in a commit view (#17446)

Author: wxiaoguang

templates/repo/diff/box.tmpl

@@ -59,7 +59,7 @@
 				{{$showFileViewToggle := or $isImage (and (not $file.IsIncomplete) $isCsv)}}
 				<div class="diff-file-box diff-box file-content {{TabSizeClass $.Editorconfig $file.Name}} mt-3" id="diff-{{.Index}}" data-old-filename="{{$file.OldName}}" data-new-filename="{{$file.Name}}" {{if $file.IsGenerated}}data-folded="true"{{end}}>
 					<h4 class="diff-file-header sticky-2nd-row ui top attached normal header df ac sb">
-						<div class="fold-file df ac">
+						<div class="df ac">
 							<a role="button" class="fold-file muted mr-2">
 								{{if $file.IsGenerated}}
 									{{svg "octicon-chevron-right" 18}}

web_src/js/features/repo-code.js

@@ -131,9 +131,8 @@ export function initRepoCodeView() {
   }
   $(document).on('click', '.fold-file', ({currentTarget}) => {
     const box = currentTarget.closest('.file-content');
-    const chevron = currentTarget.querySelector('a.chevron');
     const folded = box.dataset.folded !== 'true';
-    chevron.innerHTML = svg(`octicon-chevron-${folded ? 'right' : 'down'}`, 18);
+    currentTarget.innerHTML = svg(`octicon-chevron-${folded ? 'right' : 'down'}`, 18);
     box.dataset.folded = String(folded);
   });
   $(document).on('click', '.blob-excerpt', async ({currentTarget}) => {