Docfix.
* jc/am-doc-whitespace-action-fix:
am: align placeholder for --whitespace option with apply
'git am' [--signoff] [--keep] [--[no-]keep-cr] [--[no-]utf8] [--no-verify]
[--[no-]3way] [--interactive] [--committer-date-is-author-date]
[--ignore-date] [--ignore-space-change | --ignore-whitespace]
- [--whitespace=<option>] [-C<n>] [-p<n>] [--directory=<dir>]
+ [--whitespace=<action>] [-C<n>] [-p<n>] [--directory=<dir>]
[--exclude=<path>] [--include=<path>] [--reject] [-q | --quiet]
[--[no-]scissors] [-S[<keyid>]] [--patch-format=<format>]
[--quoted-cr=<action>]
--ignore-space-change::
--ignore-whitespace::
---whitespace=<option>::
+--whitespace=<action>::
-C<n>::
-p<n>::
--directory=<dir>::