[PATCH v1 2/5] submodule foreach: document '$sm_path' instead of '$path'

As using a variable '$path' may be harmful to users due to capitalization issues, see 64394e3ae9 (git-submodule.sh: Don't use $path variable in eval_gettext string, 2012-04-17). Adjust the documentation to advocate for using $sm_path, which contains the same value. We still make the 'path'

[PATCH v1 2/5] submodule foreach: document '$sm_path' instead of '$path'

As using a variable '$path' may be harmful to users due to capitalization issues, see 64394e3ae9 (git-submodule.sh: Don't use $path variable in eval_gettext string, 2012-04-17). Adjust the documentation to advocate for using $sm_path, which contains the same value. We still make the 'path'