Adjusting matcher comments with one-line summaries

pkg/matcher/lib/src/util.dart

Index: pkg/matcher/lib/src/util.dart
diff --git a/pkg/matcher/lib/src/util.dart b/pkg/matcher/lib/src/util.dart
index 08cba77eb49ddf6da3d9598019c1118df0e57e7b..3ecc47c5846d14842aca546698e828441a676497 100644
--- a/pkg/matcher/lib/src/util.dart
+++ b/pkg/matcher/lib/src/util.dart
@@ -15,7 +15,8 @@ void addStateInfo(Map matchState, Map values) {
   matchState.addAll(values);
 }
 
-/// Takes an argument and returns an equivalent matcher.
+/// Takes an argument and returns an equivalent [Matcher].
+///
 /// If the argument is already a matcher this does nothing,
 /// else if the argument is a function, it generates a predicate
 /// function matcher, else it generates an equals matcher.