Point to isA over TypeMatcher (#114)

See comments at https://github.com/dart-lang/matcher/issues/98#issuecomment-536785301
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1a37c52..f3ce053 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 ## 0.12.6
 
 - Update minimum Dart SDK to `2.2.0`.
+- Consistently point to `isA` as a replacement for `instanceOf`.
 
 ## 0.12.5
 
diff --git a/lib/src/core_matchers.dart b/lib/src/core_matchers.dart
index 1042cb0..204cea3 100644
--- a/lib/src/core_matchers.dart
+++ b/lib/src/core_matchers.dart
@@ -127,10 +127,9 @@
   Description describe(Description description) => description.add('anything');
 }
 
-/// **DEPRECATED** Use [TypeMatcher] instead.
+/// **DEPRECATED** Use [isA] instead.
 ///
-/// Returns a matcher that matches if an object is an instance
-/// of [T] (or a subtype).
+/// A matcher that matches if an object is an instance of [T] (or a subtype).
 @Deprecated('Use `isA<MyType>()` instead.')
 // ignore: camel_case_types
 class isInstanceOf<T> extends TypeMatcher<T> {