add pos-int? nat-int? and neg-int?

[eNotchy]

• This PR corresponds to an issue with a clear problem statement.

• This PR contains a test to prevent against future regressions

• I have updated the CHANGELOG.md file with a description of the addressed issue.

[borkdude]

@eNotchy Should we also add a function for integer? that is used in these core fns?

[eNotchy]

@eNotchy Should we also add a function for integer? that is used in these core fns?

yeah why not. How about this:

function integer_QMARK_(x) {
  return typeof x == 'bigint' || int_QMARK_(x);
}

[borkdude]

It turned out it was already added.

[borkdude]

@eNotchy Why did you have the typeof checks before Number.isInteger, those didn't seem to be necessary? I made some simplifications to that and the tests still seemed to work.

[eNotchy]

@eNotchy Why did you have the typeof checks before Number.isInteger, those didn't seem to be necessary? I made some simplifications to that and the tests still seemed to work.

You're right, my bad.