Update Warning Copy for `fontHeight` Check

[aarr0n]

Proposed changes

• Tiiiiny tweak to the warning copy for the fontHeight check.

Code quality

• [ ] I made some tests for my changes
• [ ] I added my name in the contributors field of the package.json file

License

To get your contribution merged, you must check the following.

• [x] I read the project license in the LICENSE file
• [x] I agree with publishing under this project license

My NPM username: aarr0n

[NaridaL]

Thanks @aarr0n!

[nfroidure]

Thanks @aarr0n and @NaridaL for the merge ;)