Docs: Update docs for suffix icon interaction behaviour (#169828)

Docs: Update docs for suffix icon interaction behaviour
fixes: #167713 

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

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

@@ -603,6 +603,27 @@ class TextField extends StatefulWidget {
   ///
   /// If non-null this property overrides the [decoration]'s
   /// [InputDecoration.enabled] property.
+  ///
+  /// When a text field is disabled, all of its children widgets are also
+  /// disabled, including the [InputDecoration.suffixIcon]. If you need to keep
+  /// the suffix icon interactive while disabling the text field, consider using
+  /// [readOnly] and [enableInteractiveSelection] instead:
+  ///
+  /// ```dart
+  /// TextField(
+  ///   enabled: true,
+  ///   readOnly: true,
+  ///   enableInteractiveSelection: false,
+  ///   decoration: InputDecoration(
+  ///     suffixIcon: IconButton(
+  ///       onPressed: () {
+  ///         // This will work because the TextField is enabled
+  ///       },
+  ///       icon: const Icon(Icons.edit_outlined),
+  ///     ),
+  ///   ),
+  /// )
+  /// ```
   final bool? enabled;
 
   /// Determines whether this widget ignores pointer events.