Fix positional argument default value operator from "=" to ":" in one of examples and Close parenthesis for consistency and dart correctness.

PiperOrigin-RevId: 217329602
diff --git a/lib/intl.dart b/lib/intl.dart
index aac8bee..0b201b5 100644
--- a/lib/intl.dart
+++ b/lib/intl.dart
@@ -154,7 +154,7 @@
   ///         name: "hello",
   ///         args: [yourName],
   ///         desc: "Say hello",
-  ///         examples = const {"yourName": "Sparky"}.
+  ///         examples: const {"yourName": "Sparky"});
   ///
   /// The source code will be processed via the analyzer to extract out the
   /// message data, so only a subset of valid Dart code is accepted. In