help: show value requirement and multiple occurrence of options
this helps users to know what kind of option is:
- no value is required(flag option)
- value is required
- value is required, and multiple occurrences are allowed
each kinds are shown as below:
-f --force force push
-e --ssh CMD specify ssh command to use
-b --branch BRANCH [+] a specific branch you would like to push
if one or more 3rd type options are shown, explanation for '[+]' mark
is also shown as footnote.
[ original upstream message ]