[CI SKIP] Corrections to testing guide.

Partially revert https://github.com/rails/rails/commit/c31e638a37946a120f6dbf207127d36beea5ab85.

guides/source/testing.md

@@ -787,12 +787,12 @@ Rake Tasks for Running your Tests
 
 You don't need to set up and run your tests by hand on a test-by-test basis.
 Rails comes with a number of built-in rake tasks to help in testing.
-Below table lists available commands which comes along with `Rakefile` tasks
+Below table lists available commands which come along in the default `Rakefile`
 when you initiate a Rails project.
 
 | Tasks                   | Description |
 | ----------------------- | ----------- |
-| `rake test`             | Runs all tests in the `test` folder by default |
+| `rake test`             | Runs all tests in the `test` folder. You can also simply run `rake` as Rails will run all the tests by default |
 | `rake test:controllers` | Runs all the controller tests from `test/controllers` |
 | `rake test:functionals` | Runs all the functional tests from `test/controllers`, `test/mailers`, and `test/functional` |
 | `rake test:helpers`     | Runs all the helper tests from `test/helpers` |