This function is identical to vim_isprintc when encoding=utf-8 is used
As this is the only internal encoding nvim supports, it is now redundant

ref #2905

This requires removing the "Inner expression should be aligned" rule
from clint as it prevents essentially any formatting regarding ternary
operators.

- reduce variable scope
- prefer initialization over declaration and assignment

- reduce variable scope
- prefer initialization over declaration and assignment
- use bool to represent boolean values

We already have an extensive suite of static analysis tools we use,
which causes a fair bit of redundancy as we get duplicate warnings. PVS
is also prone to give false warnings which creates a lot of work to
identify and disable.