Don't normalize the input string

[kevva]

While nifty, and visually it doesn't have an impact. However, when comparing a normalized string to a normal they can differ even though they look the same on the surface. Also, it's not needed for this module to function correctly.

See https://github.com/chalk/slice-ansi/pull/27#issuecomment-533216774 for more details.

[Qix-]

I dont think the test is necessary. It's not required but not not allowed ;)

[kevva]

@Qix-, agree :).

[Qix-]

Thanks! ❤️