fix(pp): char and string literals

[W95Psp]

Fixes #3560

Note: we should maybe print escape codes for certain ranges of code points 🤔

[mtzguido]

Thanks Lucas, looks great, merging.

Note: we should maybe print escape codes for certain ranges of code points 🤔

To properly do this kind of thing I think the lexer should retain some information of how the char was lexed/parsed, if the user writes \n we should retain that, and the same applies for \x0a. For chars computed internally we can make some default sensible choice.