Fix typos in Shallow Rendering Documentation (#8226)

* Fix typos in Shallow Rendering Documentation

* Fix another occurrence

docs/addons-test-utils.md

@@ -49,9 +49,9 @@ Shallow rendering lets you render a component "one level deep" and assert facts
 
 Call [`createRenderer()`](#createrenderer) in your tests to create a shallow renderer. You can think of this as a "place" to render the component you're testing, and from which you can extract the component's output.
 
-[`shadowRenderer.render()`](#shallowrenderer.render) is similar to [`ReactDOM.render()`](/react/docs/react-dom.html#render) but it doesn't require DOM and only renders a single level deep. This means you can test components in isolated from how their children are implemented.
+[`shallowRenderer.render()`](#shallowrenderer.render) is similar to [`ReactDOM.render()`](/react/docs/react-dom.html#render) but it doesn't require DOM and only renders a single level deep. This means you can test components isolated from how their children are implemented.
 
-After `shadowRenderer.render()` has been called, you can use [`shallowRenderer.getRenderOutput()`](#shallowrenderer.getrenderoutput) to get the shallowly rendered output.
+After `shallowRenderer.render()` has been called, you can use [`shallowRenderer.getRenderOutput()`](#shallowrenderer.getrenderoutput) to get the shallowly rendered output.
 
 You can then begin to assert facts about the output. For example, if your component's render method returns: