deprecated consistency (#75903)

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

@@ -98,6 +98,10 @@ class FlatButton extends MaterialButton {
   /// at the start, and 16 at the end, with an 8 pixel gap in between.
   ///
   /// The [icon], [label], and [clipBehavior] arguments must not be null.
+  @Deprecated(
+    'Use TextButton instead. See the migration guide in flutter.dev/go/material-button-migration-guide). '
+    'This feature was deprecated after v1.26.0-18.0.pre.'
+  )
   factory FlatButton.icon({
     Key? key,
     required VoidCallback? onPressed,

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

@@ -107,6 +107,10 @@ class OutlineButton extends MaterialButton {
   ///
   /// The [highlightElevation] argument must be null or a positive value. The
   /// [icon], [label], [autofocus], and [clipBehavior] arguments must not be null.
+  @Deprecated(
+    'Use OutlinedButton instead. See the migration guide in flutter.dev/go/material-button-migration-guide). '
+    'This feature was deprecated after v1.26.0-18.0.pre.'
+  )
   factory OutlineButton.icon({
     Key? key,
     required VoidCallback? onPressed,

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

@@ -116,6 +116,10 @@ class RaisedButton extends MaterialButton {
   ///
   /// The [elevation], [highlightElevation], [disabledElevation], [icon],
   /// [label], and [clipBehavior] arguments must not be null.
+  @Deprecated(
+    'Use ElevatedButton instead. See the migration guide in flutter.dev/go/material-button-migration-guide). '
+    'This feature was deprecated after v1.26.0-18.0.pre.'
+  )
   factory RaisedButton.icon({
     Key? key,
     required VoidCallback? onPressed,

packages/flutter/lib/src/widgets/framework.dart

@@ -269,6 +269,10 @@ class GlobalObjectKey<T extends State<StatefulWidget>> extends GlobalKey<T> {
 @optionalTypeArgs
 class TypeMatcher<T> {
   /// Creates a type matcher for the given type parameter.
+  @Deprecated(
+    'TypeMatcher has been deprecated because it is no longer used in framework(only in deprecated methods). '
+    'This feature was deprecated after v1.12.1.'
+  )
   const TypeMatcher();
 
   /// Returns true if the given object is of type `T`.

packages/flutter_web_plugins/lib/src/plugin_registry.dart

@@ -189,16 +189,20 @@ class Registrar extends BinaryMessenger {
 /// as part of a simplification of the web plugins API.
 @Deprecated(
   'Use Registrar instead. '
-  'This feature was deprecated after v1.24.0-7.0.pre.'
+  'This feature was deprecated after v1.26.0-18.0.pre.'
 )
 class PluginRegistry extends Registrar {
   /// Creates a [Registrar].
   ///
   /// The argument is ignored.
+  @Deprecated(
+    'Use Registrar instead. '
+    'This feature was deprecated after v1.26.0-18.0.pre.'
+  )
   PluginRegistry([
     @Deprecated(
       'This argument is ignored. '
-      'This feature was deprecated after v1.24.0-7.0.pre.'
+      'This feature was deprecated after v1.26.0-18.0.pre.'
     )
     BinaryMessenger? binaryMessenger,
   ]) : super(); // ignore: avoid_unused_constructor_parameters
@@ -206,7 +210,7 @@ class PluginRegistry extends Registrar {
   /// Returns `this`. The argument is ignored.
   @Deprecated(
     'This method is redundant. It returns the object on which it is called. '
-    'This feature was deprecated after v1.24.0-7.0.pre.'
+    'This feature was deprecated after v1.26.0-18.0.pre.'
   )
   Registrar registrarFor(Type key) => this;
 }