`/a/**` is understood by `Path.full_match` as `/a` followed by multiple segments, at least one

Bug report

Bug description:

/a/** is understood by Path.full_match as "/a followed by multiple segments, at least one", instead of "/a followed by multiple segments, including zero".

From https://docs.python.org/3/library/pathlib.html#pathlib-pattern-language

** (entire segment)
Matches any number of file or directory segments, including zero.

# one segment per **
Path('/a/b').full_match('/a/**') # True
# zero segments per **
Path('/a').full_match('/a/**') # False - expected True
# interestingly
Path('/').full_match('/**') # True

CPython versions tested on:

3.13

Operating systems tested on:

Linux

Linked PRs

• gh-151479

Start with the pathlib Path.full_match entry point and compare its behavior with the documented pattern language for . Reproduce the /a/ and /** examples, then add regression coverage showing that ** matches zero segments; the linked PR gh-151479 indicates work is already underway.