Add missing space (#29393) (#29399)

Backport #29393 by @KN4CK3R

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>

templates/repo/diff/options_dropdown.tmpl

@@ -13,7 +13,7 @@
 			<a class="item" href="{{$.RepoLink}}/commit/{{PathEscape .Commit.ID.String}}.diff" download="{{ShortSha .Commit.ID.String}}.diff">{{ctx.Locale.Tr "repo.diff.download_diff"}}</a>
 		{{end}}
 		<a id="expand-files-btn" class="item">{{ctx.Locale.Tr "repo.pulls.expand_files"}}</a>
-		<a id="collapse-files-btn"class="item">{{ctx.Locale.Tr "repo.pulls.collapse_files"}}</a>
+		<a id="collapse-files-btn" class="item">{{ctx.Locale.Tr "repo.pulls.collapse_files"}}</a>
 		{{if .Issue.Index}}
 			{{if .ShowOutdatedComments}}
 				<a class="item" href="?style={{if $.IsSplitStyle}}split{{else}}unified{{end}}&whitespace={{$.WhitespaceBehavior}}&show-outdated=false">