fix: validate binary_and inputs

[nishanty23]

Description

This PR improves input validation in binary_and().

Changes

• Raise TypeError when either input is not an integer.
• Correct the negative-input error message from "positive" to "non-negative".
• Update doctests to verify the new validation behavior.
• Add a doctest covering an invalid second argument.

Testing

• python -m doctest -v bit_manipulation/binary_and_operator.py
• ruff check bit_manipulation/binary_and_operator.py

[cclauss]

ON HOLD: Our focus is on merging or closing old pull requests before October 1st.

• https://hacktoberfest.com

[priya-sundaram-dev]

Nice cleanup — this turns the previous confusing failures (Unknown format code 'b' for object of type 'float', and the str-vs-int comparison error) into clear, intentional TypeErrors, and "non-negative" is the accurate wording since 0 is allowed by the a < 0 check. I ran the doctests and they pass.

One thing worth a conscious decision (not a blocker): type(a) is not int deliberately rejects bool, since bool is a subclass of int. So binary_and(True, False) now raises TypeError rather than treating them as 1/0. That's defensible (booleans aren't really the intended input here), but if you'd rather accept them you'd use isinstance(a, int). Whichever you choose, a one-line doctest pinning the bool behavior would make the intent explicit.

Otherwise this LGTM. Approving.

[cclauss]

Please add that doctest.