i18n [nfc]: Standardize a todo-i18n comment, from "intl"

We have a number of comments saying `TODO(i18n)`, and just this one
saying `TODO(intl)`.  The variation makes it less effective at its
purpose of being findable with grep.

Author: gnprice

lib/widgets/content.dart

@@ -1214,7 +1214,7 @@ class GlobalTime extends StatelessWidget {
   final GlobalTimeNode node;
   final TextStyle ambientTextStyle;
 
-  static final _dateFormat = DateFormat('EEE, MMM d, y, h:mm a'); // TODO(intl): localize date
+  static final _dateFormat = DateFormat('EEE, MMM d, y, h:mm a'); // TODO(i18n): localize date
 
   @override
   Widget build(BuildContext context) {