Merge branch 'sb/submodule-ignore-trailing-slash'

A minor regression fix for "git submodule".

* sb/submodule-ignore-trailing-slash:
  t0060: sidestep surprising path mangling results on Windows
  submodule: ignore trailing slash in relative url
  submodule: ignore trailing slash on superproject URL

diff --cc builtin/submodule--helper.c
Simple merge