Specify language in neverCalled docs for nicer formatting in docs (da…

…rt-archive/matcher#230)

This will also allow dartdoc's `missing-code-block-language` warning in
Flutter.

pkgs/matcher/CHANGELOG.md

@@ -1,3 +1,5 @@
+## 0.12.17-wip
+
 ## 0.12.16
 
 * Expand bounds on `test_api` dependency to allow the next breaking release

pkgs/matcher/lib/src/expect/never_called.dart

@@ -17,7 +17,7 @@ import 'util/pretty_print.dart';
 /// This can safely be passed in place of any callback that takes ten or fewer
 /// positional parameters. For example:
 ///
-/// ```
+/// ```dart
 /// // Asserts that the stream never emits an event.
 /// stream.listen(neverCalled);
 /// ```

pkgs/matcher/pubspec.yaml

@@ -1,5 +1,5 @@
 name: matcher
-version: 0.12.16
+version: 0.12.17-wip
 description: >-
   Support for specifying test expectations via an extensible Matcher class.
   Also includes a number of built-in Matcher implementations for common cases.