Docs: fix incorrect reference in bin() documentation

[BHUVANSH855]

Fix an incorrect reference to enum.bin in the documentation for the built-in bin() function.

The reference pointed to a non-existent function. It has been replaced with a correct explanation of how negative integers are represented, along with a reference to format() for further details on binary representations.

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #32464519 | 📁 Comparing 33d493e against main (d71e3bc)

  🔍 Preview build  

2 files changed

± download.html
± library/functions.html

[BHUVANSH855]

This is a small documentation fix that does not require a separate issue.

Could a maintainer please add the skip issue label?

[picnixz]

enum.bin exists and its purpose is correct: https://docs.python.org/3/library/enum.html#enum.bin.