docs: fix typo usued -> used

[HonkingGoose]

Why:

Closes #3532

What's being changed:

• Fix typo: usued -> used

Check off the following:

• I have reviewed my changes in staging. (look for the deploy-to-heroku link in your pull request, then click View deployment)
• For content changes, I have reviewed the localization checklist
• For content changes, I have reviewed the Content style guide for GitHub Docs.

[github-actions]

👋 Hey there spelunker. It looks like you've modified some files that we can't accept as contributions. The complete list of files we can't accept are:
translations/**
lib/rest/static/**
.github/workflows/**
.github/CODEOWNERS
translations/**
assets/fonts/**
data/graphql/**
lib/graphql/**
lib/redirects/**
lib/rest/**
lib/webhooks/**

You'll need to revert all of the files you changed in that list using GitHub Desktop or git checkout origin/main <file name>. Once you get those files reverted, we can continue with the review process.