This change updates the doc comments of the various ParseGlob functions
and methods to state that they use the semantics of filepath.Match when
matching the file name pattern.

Fixes #30608

Change-Id: Iee4bdc0a2a2f8647d1f9a910e4d72a5de9204d11
Reviewed-on: https://go-review.googlesource.com/c/go/+/179739Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>