Refactor util.go

[zeek0x]

• add Min16, Constrain16, AsUint32
• unify Min*, Max* inequalities to > or < excluding >= or <=
• omit types of function arguments

[junegunn]

• sort functions

I'd rather not do this, it makes it hard to see the diff or track the changes (git blame) in a line range.

You see it's hard to see if the moved functions are the same as before or not: https://github.com/junegunn/fzf/pull/3065/files

[junegunn]

omit types of function arguments

I'm just being curious. Is this the recommended style these days? Are you following a specific Go style guide? The code we're discussing here dates back to early 2015. I don't recall following any style guides back then. I wonder if the community standard has evolved over time.