chore: add c/cpp/auto options in code langauges

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/code_block/code_block_component.dart

@@ -123,7 +123,7 @@ class _CodeBlockComponentWidgetState extends State<CodeBlockComponentWidget>
     'BASIC',
     'C',
     'C#',
-    'C++',
+    'CPP',
     'Clojure',
     'CSS',
     'Dart',
@@ -167,7 +167,10 @@ class _CodeBlockComponentWidgetState extends State<CodeBlockComponentWidget>
       .map((e) => e.toLowerCase())
       .toSet()
       .intersection(allLanguages.keys.toSet())
-      .toList();
+      .toList()
+    ..add('auto')
+    ..add('c')
+    ..sort();
 
   late final editorState = context.read<EditorState>();
 
@@ -253,7 +256,7 @@ class _CodeBlockComponentWidgetState extends State<CodeBlockComponentWidget>
         alignment: Alignment.centerLeft,
         padding: const EdgeInsets.symmetric(horizontal: 4),
         child: FlowyTextButton(
-          '${language?.capitalize() ?? 'auto'} ',
+          '${language?.capitalize() ?? 'Auto'} ',
           padding: const EdgeInsets.symmetric(
             horizontal: 12.0,
             vertical: 4.0,
@@ -281,7 +284,7 @@ class _CodeBlockComponentWidgetState extends State<CodeBlockComponentWidget>
   Future<void> updateLanguage(String language) async {
     final transaction = editorState.transaction
       ..updateNode(node, {
-        CodeBlockKeys.language: language,
+        CodeBlockKeys.language: language == 'auto' ? null : language,
       })
       ..afterSelection = Selection.collapse(
         node.path,