re-word a few things

Author: PaulieScanlon

CONTRIBUTING.md

@@ -49,23 +49,29 @@ Twitter
 ## Testing WIP
 
 Each component will at some point require at least one test to check it renders correctly. Each component in
-`mdx-embed/src/components/` is wrapped in what we call the **GeneralObserver** This component is responsible for
-ensuring the 3rd party embed script isn't invoked until the component has entered the viewport. This is particularly
-important for Lighthouse scores and page load speeds. If a blog post page for example has 10 or 15 embed codes, Twitter,
-CodePend, YouTube etc on the page we don't want to load all that 3rd party JavaScript until the reader has scrolled down
-to where the component is used. When it scrolls in to view **GeneralObserver** which is an
+`mdx-embed/src/components/` is wrapped in what we call the **GeneralObserver**.
+
+This component is responsible for ensuring the 3rd party embed script isn't invoked until the component has entered the
+viewport. This is particularly important for Lighthouse scores and page load speeds. If a blog post for example has 10
+or 15 embed codes, Twitter, CodePen, YouTube etc on the page we don't want to load all that 3rd party JavaScript right
+away, instead we wait until the reader has scrolled down to where the component is used and when the component is "in
+view" **GeneralObserver** which is an
 [Intersection Observer](https://developer.mozilla.org/en-US/docs/Web/API/Intersection_Observer_API) triggers a React
 state change which causes the children to be rendered in the DOM
 
-This presents an issue when we come to test the components because we need to fake the "scrolled in to view" action
+This presents an issue when we come to testing the components because we need to fake the "scrolled in to view" action
 which allows the children of **GeneralObserver** to render.
 
-To _mock_ this is a test we've globally exposed a method called `triggerGeneralObserver()` and since we're using Testing
+To _mock_ this in a test we've globally exposed a method called `triggerGeneralObserver()` and since we're using Testing
 Library this state change must be wrapped in an [act](https://testing-library.com/docs/react-testing-library/api#act).
 
-With that said we require each `test(() => {})` to contain an `act(() => {})` and a call to `triggerGeneralObserver()`
+With that said we require each `test(() => {...})` to contain an `act(() => {...})` and a call to
+`triggerGeneralObserver()`
+
+That looks like something like the below:
 
-That looks like something like this: the `(window as any)` is a TypeScript thing... Paul is working on it.
+- The `(window as any)` is a TypeScript thing... Paul is working on it,
+- act must return something even, `undefined` is ok
 
 ```javascript
 describe('<CodePen />', () => {