[ linter ] Add diagnostic docs for avoid_catches_without_on_clauses

Closes https://github.com/dart-lang/sdk/pull/63091

GitOrigin-RevId: dc7973d9519ee66691bc0ea1667d8f6382bf6584
Change-Id: If2dab19ebdd9592f032c47cd3f17622fd4f35686
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/492282
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Connie Ooi <connieooi@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

pkg/linter/messages.yaml

@@ -989,6 +989,41 @@ LinterLintCode:
       stable: "2.0"
     categories: [effectiveDart, style]
     hasPublishedDocs: false
+    documentation: |-
+      #### Description
+
+      The analyzer produces this diagnostic when a `catch` clause lacks an
+      `on` clause to specify the exception type. Catching all exceptions
+      can mask unexpected errors and make debugging more difficult.
+
+      #### Example
+
+      The following code produces this diagnostic because the `catch` clause
+      has no `on` clause to specify the exception type:
+
+      ```dart
+      void f() {
+        try {
+          int.parse('?');
+        } [!catch!] (e) {
+          print(e);
+        }
+      }
+      ```
+
+      #### Common fixes
+
+      Add an `on` clause to specify the type of exception to catch:
+
+      ```dart
+      void f() {
+        try {
+          int.parse('?');
+        } on FormatException catch (e) {
+          print(e);
+        }
+      }
+      ```
     deprecatedDetails: |-
       From [Effective Dart](https://dart.dev/effective-dart/usage#avoid-catches-without-on-clauses):