Merge branch 'nd/remote-update-doc'

"git remote update" can take both a single remote nickname and a
nickname for remote groups, but only one of them was documented.

* nd/remote-update-doc:
  remote: doc typofix
  remote.txt: update documentation for 'update' command

Documentation/git-remote.txt

@@ -186,8 +186,8 @@ actually prune them.
 
 'update'::
 
-Fetch updates for a named set of remotes in the repository as defined by
-remotes.<group>.  If a named group is not specified on the command line,
+Fetch updates for remotes or remote groups in the repository as defined by
+remotes.<group>.  If neither group nor remote is specified on the command line,
 the configuration parameter remotes.default will be used; if
 remotes.default is not defined, all remotes which do not have the
 configuration parameter remote.<name>.skipDefaultUpdate set to true will