FIX a bug: integer type resolution

[MustBastani]

Hi,

I noticed a bug in the integer type resolver when determining the bit width of signed integers.

For example, for a range like -140..=-44, it assigns 8 bits, even though an i8 can only store values in the range -128..=127.

The problematic line is primarily in: https://github.com/FICS/asnfuzzgen/blob/0d82d8e6f1a43f7fe685852b7f19dc6ee0b31d3f/asnfuzzgen/src/resolver/asn/types/base/integer.rs#L39 However, my pull request includes additional changes to address the various integer bit widths.