fix: various, mostly from cargo clippy -- --warn clippy::pedantic

[JeromeSchmied]

Code improvement

Description

Various code improvements, to make the code more readable, efficient and more Rusty

• many functions from utils.rs were self impls -> removed them
• in some cases, no mut was needed, instead of for ... ....iter().collect() was enough
• applied numerous cargo clippy -- --warn clippy::pedantic fixes, eg.
  • unnecessary_not_if
  • let ... else
  • in some cases take Coord as value instead of reference, as it's more efficient
  • add ; to line-end if not returning
  • format!("{}", x) can be format!("{x}")
  • identical match branches
  • String::new() instead of "".to_string()
  • some fn-s take &str instead of String

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• My changes generate no new warnings, actually the opposite!
• New and existing unit tests pass locally with my changes

[thomas-mauran]

Nice fixes, we are having an overflow when eating a another piece thought we need to fix that

[JeromeSchmied]

Nice fixes, we are having an overflow when eating a another piece thought we need to fix that

I'm sorry, didn't quite understand that.

[thomas-mauran]

Nice fixes, we are having an overflow when eating a another piece thought we need to fix that

I'm sorry, didn't quite understand that.

To reproduce the bug I found while running on your branch run a classic game, move a white pawn twice, same for black, then eat the black pawn with the white one and the game should quit with a rust panick

[JeromeSchmied]

Actually it's interesting, because as far as I'm concerned, no code logic was changed before, so it shouldn't have happened, but luckily enough it seems to be fixed now, by commit a0a829b.

[thomas-mauran]

Actually it's interesting, because as far as I'm concerned, no code logic was changed before, so it shouldn't have happened, but luckily enough it seems to be fixed now, by commit a0a829b.

This is very weird yes, I'm gonna check in detail this commit tonight thank you for fixing it !

[thomas-mauran]

Perfect thanks again for yet another contribution @JeromeSchmied