Use correct branch for .editorconfig error (#21152)

In #21088 I accidentally forgot to support multiple branches. It always
checks the default branch, no matter on which branch you are working on.
With this fix, it always shows the error from the current branch. Sorry
for that.

routers/web/repo/view.go

@@ -375,7 +375,7 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 	ctx.Data["RawFileLink"] = rawLink + "/" + util.PathEscapeSegments(ctx.Repo.TreePath)
 
 	if ctx.Repo.TreePath == ".editorconfig" {
-		_, editorconfigErr := ctx.Repo.GetEditorconfig()
+		_, editorconfigErr := ctx.Repo.GetEditorconfig(ctx.Repo.Commit)
 		ctx.Data["FileError"] = editorconfigErr
 	}