Fixes "Edit this page" link in docs

[lmac-1]

This PR fixes the "Edit this page" link at the bottom of the docs. I had a look at the docusaurus docs to see how to fix this.

For someone without a fork of the repository, it will look like this when they click to edit the docs:

If they already have a fork of the application, it will take them to edit the page on their fork:

It then makes a commit in your fork and takes you to the screen to open a pull request straight away:

I've tested this locally and seems to be working well.

[netlify[bot]]

‼️ Deploy request for useshoppingcart rejected.

Name	Link
🔨 Latest commit	f678e467f710144527dd3deca7f3a7515fea719b

[dayhaysoos]

@all-contributors please add @lmac-1 for docs, content, and example

[allcontributors[bot]]

@dayhaysoos

I've put up a pull request to add @lmac-1! :tada: