[BUG] 'git status --ignored' <pathspec> matches partial names

Steps to reproduce:

git init foo
cd foo
mkdir bar
echo bar/ >.gitignore
git init bar/baz
git init bar/quux
git status --porcelain --ignored --untracked-files -- ba

Expected output:
none, "ba" doesn't match "bar".

Actual output:
!! bar/baz/
!! bar/quux/

Credits to Lester Longley for the reproduction, in Emacs bug#81625.

-- 
Sean Whitton