fixed a grammar error

[tiagohermano]

Description

Fixed grammar on the word 'mean' to 'means'

Related Issues

[m-allanson]

Thanks @tiagohermano! I think mean and means are both fine here. How about re-wording this sentence to avoid using that word? We can also explain what Jest is, which I think should be a bit clearer? Something like this:

- However there are a few features of the Gatsby build process that means the standard Jest setup doesn't quite work. This guide shows you how to set it up.
+ In this guide you'll learn how to run unit tests for your Gatsby site using a test framework called Jest.

[DSchau]

@tiagohermano would you have some time to address the changes that @m-allanson suggested?

Please let us know, thank you!

[DSchau]

Going to close this out--if you're able to make the changes @m-allanson suggested, we'd be happy to take another look.

Thanks for your contribution!