Merge pull request #9966 from HerrickSpencer/patch-3

Documentation of writing add-on: replace 'withFoo' with the name of addon used in sample below 'withMyAddon'

docs/src/pages/addons/writing-addons/index.md

@@ -130,7 +130,7 @@ Now we need to create two files, `register.js` and `index.js,`. `register.js` wi
 
 ## Creating a decorator
 
-Let's add the following content to the `index.js`. It will expose a decorator called `withFoo` which we use the `.addDecorator()` API to decorate all our stories.
+Let's add the following content to the `index.js`. It will expose a decorator called `withMyAddon` which we use the `.addDecorator()` API to decorate all our stories.
 
 The `@storybook/addons` package contains a `makeDecorator` function which we can use to create such a decorator: