Argparse negative number parsing does not capture -.5

[savannahostrowski]

https://github.com/python/cpython/pull/123970/files#r1770614169

Linked PRs

• GH-124321: Argparse negative number parsing does not capture -.5  #124322
• [3.13] GH-124321: Fix argparse negative number parsing to capture -.5(GH-124322) #124359
• [3.12] GH-124321: Fix argparse negative number parsing to capture -.5(G… #124361