Lint readme

[wolf99]

Hiya,
This PR lints the readme according to markdownlint rules.

If interested, I could add a further PR that adds a workflow that adds a markdown lint checker?

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[wolf99]

I've attempted to add the GitHub email address (e.g. <number>+<username>@users.noreply.github.com) that is used to sign these commits, to my Google account, so that I can sign the CLA with that email address.
However the Google account settings requires alternative emails addresses to be verified. As the GitHub email address is not actually an email address as such, this is not possible.
I have signed the CLA using my personal email address but I will not be using that here due to wishing to retain my privay.

Maintainers can chose either:

• Fix the Google account requirements for verification of alternative email addresses for services like GitHub
• Ignore the exact details for the CLA requirement and take my word that I have signed it with my personal address and merge this PR
• Ignore this PR

As you like 🙂

[G-Rath]

Thanks - personally I think it would be best to set CI up to check this, ideally with prettier with proseWrap set to always too; is that something you'd be ok to do?

I can't speak for the CLA requirement, though I suspect it probably can't be wavered but again I'm happy to put my name against it if you're ok with that; alternatively I'm happy to handle the whole thing :)

(sorry about closing, I fat-fingered the button 😅)

[oliverchang]

Looks like the CLA is passing now! Thanks for contribution @wolf99.

[oliverchang]

/gcbrun