Corrects typo in source example of ParametersRunnerFactory.

Closes #1085

Author: Adrian Cole

src/main/java/org/junit/runners/Parameterized.java

@@ -140,7 +140,7 @@
  * The factory must have a public zero-arg constructor.
  *
  * <pre>
- * public class YourRunnerFactory implements ParameterizedRunnerFactory {
+ * public class YourRunnerFactory implements ParametersRunnerFactory {
  *     public Runner createRunnerForTestWithParameters(TestWithParameters test)
  *             throws InitializationError {
  *         return YourRunner(test);

src/main/java/org/junit/runners/parameterized/ParametersRunnerFactory.java

@@ -4,7 +4,7 @@
 import org.junit.runners.model.InitializationError;
 
 /**
- * A {@code ParameterizedRunnerFactory} creates a runner for a single
+ * A {@code ParametersRunnerFactory} creates a runner for a single
  * {@link TestWithParameters}.
  * 
  * @since 4.12