Be ready for numbers, undefined and null

[ai]

Default JS is not type safe. It is very easy to make a mistake and send number to red(result).

It will be much easy to migrate projects if types will support at least numbers and code will be ready for numbers, undefined and null.

[alexeyraspopov]

Now that we have benchmarks, I think it should be easier to iterate on this thing. My initial idea was to not introduce any sort of input checking, assuming users either will face the runtime error during testing and fix it or simply use type checking systems.

[ai]

assuming users either will face the runtime error during testing and fix it or simply use type checking systems

There are 2 problems with it:

1. Sometimes variables can be string or undefined, which will block users from catching all errors during test
2. Current stacktrace on non-string value is confusing. It is easy to miss that picocolors works only with strings (because all other works with other values).