Rollup merge of #71366 - faern:use-assoc-int-consts3, r=dtolnay

Rollup merge of #71366 - faern:use-assoc-int-consts3, r=dtolnay

Use assoc int consts3

Define module level int consts with associated constants instead of `min_value()` and `max_value()`. So the code become consistent with what the docs recommend etc. Seems natural.

Also remove the last usages of the int module constants from this repo (except src/test/ directory which I have still not really done anything in). Some places were missed in the previous PRs because the code uses `crate::<IntTy>` to reach the constants.

This is a continuation of #70857

r? @dtolnay