Minor fix for LiveTest's documentation.

lib/src/backend/live_test.dart

Index: lib/src/backend/live_test.dart
diff --git a/lib/src/backend/live_test.dart b/lib/src/backend/live_test.dart
index dab5ff857fb7521793df016e78a85524399a623e..8aa81824ddb072e217dc95af5f21a84a089031fe 100644
--- a/lib/src/backend/live_test.dart
+++ b/lib/src/backend/live_test.dart
@@ -11,9 +11,9 @@ import 'test.dart';
 
 /// A runnable instance of a test.
 ///
-/// This is distinct from [Test] in order to keep [Test]. Running a test
-/// requires state, and [LiveTest] provides a view of the state of the test as
-/// it runs.
+/// This is distinct from [Test] in order to keep [Test] immutable. Running a
+/// test requires state, and [LiveTest] provides a view of the state of the test
+/// as it runs.
 ///
 /// If the state changes, [state] will be updated before [onStateChange] fires.
 /// Likewise, if an error is caught, it will be added to [errors] before being