Add invisible_characters

[0xLucqs]

What it does

Checks for invisible Unicode characters in the code.

Why is this bad?

Having an invisible character in the code makes for all sorts of April fools, but otherwise is very much frowned upon.

Example

You don’t see it, but there may be a zero-width space or soft hyphen some­where in this tex

[fishonamos]

I can take this as well @0xLucqs . I have started the other.

[onlydustapp]

Hey @fishonamos!
Thanks for showing interest.
We've created an application for you to contribute to Cairo lint.
Go check it out on OnlyDust!

[CristopherAguilar10]

Hello @0xLucqs, I would like to work on this issue, I have a possible solution and I would like to help.

[onlydustapp]

Hey @CristopherAguilar10!
Thanks for showing interest.
We've created an application for you to contribute to Cairo lint.
Go check it out on OnlyDust!

[0xLucqs]

no @fishonamos only 1 issue at a time