content [nfc]: Rename UserMention widget to Mention

And update it to accept the generic `MentionNode` node.

Author: rajveermalviya

lib/widgets/content.dart

@@ -1037,9 +1037,9 @@ class _InlineContentBuilder {
       case InlineCodeNode():
         return _buildInlineCode(node);
 
-      case UserMentionNode():
+      case MentionNode():
         return WidgetSpan(alignment: PlaceholderAlignment.middle,
-          child: UserMention(ambientTextStyle: widget.style, node: node));
+          child: Mention(ambientTextStyle: widget.style, node: node));
 
       case UnicodeEmojiNode():
         return TextSpan(text: node.emojiUnicode, recognizer: _recognizer,
@@ -1117,15 +1117,15 @@ class _InlineContentBuilder {
 
 const kInlineCodeFontSizeFactor = 0.825;
 
-class UserMention extends StatelessWidget {
-  const UserMention({
+class Mention extends StatelessWidget {
+  const Mention({
     super.key,
     required this.ambientTextStyle,
     required this.node,
   });
 
   final TextStyle ambientTextStyle;
-  final UserMentionNode node;
+  final MentionNode node;
 
   @override
   Widget build(BuildContext context) {

test/widgets/content_test.dart

@@ -658,7 +658,7 @@ void main() {
     });
   });
 
-  group('UserMention', () {
+  group('Mention', () {
     testContentSmoke(ContentExample.userMentionPlain);
     testContentSmoke(ContentExample.userMentionSilent);
     testContentSmoke(ContentExample.groupMentionPlain);
@@ -670,10 +670,10 @@ void main() {
     testContentSmoke(ContentExample.legacyChannelWildcardMentionSilent);
     testContentSmoke(ContentExample.legacyChannelWildcardMentionSilentClassOrderReversed);
 
-    UserMention? findUserMentionInSpan(InlineSpan rootSpan) {
-      UserMention? result;
+    Mention? findMentionWidgetInSpan(InlineSpan rootSpan) {
+      Mention? result;
       rootSpan.visitChildren((span) {
-        if (span case (WidgetSpan(child: UserMention() && var widget))) {
+        if (span case (WidgetSpan(child: Mention() && var widget))) {
           result = widget;
           return false;
         }
@@ -682,7 +682,7 @@ void main() {
       return result;
     }
 
-    TextStyle textStyleFromWidget(WidgetTester tester, UserMention widget, String mentionText) {
+    TextStyle textStyleFromWidget(WidgetTester tester, Mention widget, String mentionText) {
       return mergedStyleOf(tester,
         findAncestor: find.byWidget(widget), mentionText)!;
     }
@@ -691,7 +691,7 @@ void main() {
       await checkFontSizeRatio(tester,
         targetHtml: '<span class="user-mention" data-user-id="13313">@Chris Bobbe</span>',
         targetFontSizeFinder: (rootSpan) {
-          final widget = findUserMentionInSpan(rootSpan);
+          final widget = findMentionWidgetInSpan(rootSpan);
           final style = textStyleFromWidget(tester, widget!, '@Chris Bobbe');
           return style.fontSize!;
         });
@@ -704,7 +704,7 @@ void main() {
         '<p><span class="user-mention silent" data-user-id="2187">Greg Price</span></p>'),
       styleFinder: (tester) {
         return textStyleFromWidget(tester,
-          tester.widget(find.byType(UserMention)), 'Greg Price');
+          tester.widget(find.byType(Mention)), 'Greg Price');
       });
 
     // TODO(#647):
@@ -718,7 +718,7 @@ void main() {
         '<h1><span class="user-mention silent" data-user-id="13313">Chris Bobbe</span></h1>'),
       styleFinder: (tester) {
         return textStyleFromWidget(tester,
-          tester.widget(find.byType(UserMention)), 'Chris Bobbe');
+          tester.widget(find.byType(Mention)), 'Chris Bobbe');
       });
 
     // TODO(#647):