fix: don't loop when matches is empty

[ItsJimi]

Hi,

I've got an error on MdiIcons.fromString when Iterable<Match> matches = exp.allMatches(str); in MdiIcons.toCamelCase match nothing because for (Match m in matches) has an empty Iterable.
Let me know if you have requests.

Thanks

[ziofat]

That's weird, which icon can trigger this?

[ItsJimi]

That's weird, which icon can trigger this?

I have this error with an empty string in parameter of MdiIcons.fromString but i think it crash for every string who don't match with the regex.
Thanks for the merge.