Update FAQ heading grammar

[hannahblair]

Warn Checklist

• [ ] This changes the interface and requires a Major/Minor version change.
• [ ] I have :tophat:'d these changes by using the commands I changed by hand.
• [ ] I have added a dependancy to the project.
• [ ] I have considered any potential impact on node-themekit

[andyw8]

Thanks @hannahblair, you'll just need to sign the CLA: https://cla.shopify.com/

[hannahblair]

@andyw8 Hey, I’ve signed the Individual Contributor CLA. Any reason why the check hasn’t passed still?

I tried to sign it again but it said this user has already signed a CLA.

[andyw8]

I re-triggered the check, all good now, thanks!