Fix `fooTheme.of(context);` usage docs (#98402)

packages/flutter/lib/src/material/drawer_theme.dart

@@ -144,7 +144,7 @@ class DrawerTheme extends InheritedTheme {
   /// Typical usage is as follows:
   ///
   /// ```dart
-  /// DrawerTheme theme = DrawerTheme.of(context);
+  /// DrawerThemeData theme = DrawerTheme.of(context);
   /// ```
   static DrawerThemeData of(BuildContext context) {
     final DrawerTheme? drawerTheme = context.dependOnInheritedWidgetOfExactType<DrawerTheme>();

packages/flutter/lib/src/material/elevated_button_theme.dart

@@ -107,7 +107,7 @@ class ElevatedButtonTheme extends InheritedTheme {
   /// Typical usage is as follows:
   ///
   /// ```dart
-  /// ElevatedButtonTheme theme = ElevatedButtonTheme.of(context);
+  /// ElevatedButtonThemeData theme = ElevatedButtonTheme.of(context);
   /// ```
   static ElevatedButtonThemeData of(BuildContext context) {
     final ElevatedButtonTheme? buttonTheme = context.dependOnInheritedWidgetOfExactType<ElevatedButtonTheme>();

packages/flutter/lib/src/material/navigation_bar_theme.dart

@@ -211,7 +211,7 @@ class NavigationBarTheme extends InheritedTheme {
   /// Typical usage is as follows:
   ///
   /// ```dart
-  /// NavigationBarTheme theme = NavigationBarTheme.of(context);
+  /// NavigationBarThemeData theme = NavigationBarTheme.of(context);
   /// ```
   static NavigationBarThemeData of(BuildContext context) {
     final NavigationBarTheme? navigationBarTheme = context.dependOnInheritedWidgetOfExactType<NavigationBarTheme>();

packages/flutter/lib/src/material/navigation_rail_theme.dart

@@ -219,7 +219,7 @@ class NavigationRailTheme extends InheritedTheme {
   /// Typical usage is as follows:
   ///
   /// ```dart
-  /// NavigationRailTheme theme = NavigationRailTheme.of(context);
+  /// NavigationRailThemeData theme = NavigationRailTheme.of(context);
   /// ```
   static NavigationRailThemeData of(BuildContext context) {
     final NavigationRailTheme? navigationRailTheme = context.dependOnInheritedWidgetOfExactType<NavigationRailTheme>();

packages/flutter/lib/src/material/outlined_button_theme.dart

@@ -107,7 +107,7 @@ class OutlinedButtonTheme extends InheritedTheme {
   /// Typical usage is as follows:
   ///
   /// ```dart
-  /// OutlinedButtonTheme theme = OutlinedButtonTheme.of(context);
+  /// OutlinedButtonThemeData theme = OutlinedButtonTheme.of(context);
   /// ```
   static OutlinedButtonThemeData of(BuildContext context) {
     final OutlinedButtonTheme? buttonTheme = context.dependOnInheritedWidgetOfExactType<OutlinedButtonTheme>();

packages/flutter/lib/src/material/text_button_theme.dart

@@ -107,7 +107,7 @@ class TextButtonTheme extends InheritedTheme {
   /// Typical usage is as follows:
   ///
   /// ```dart
-  /// TextButtonTheme theme = TextButtonTheme.of(context);
+  /// TextButtonThemeData theme = TextButtonTheme.of(context);
   /// ```
   static TextButtonThemeData of(BuildContext context) {
     final TextButtonTheme? buttonTheme = context.dependOnInheritedWidgetOfExactType<TextButtonTheme>();