@addtogroup has wrong regexp (missing hyphen)

Migrated issue

Reported by: jhodgdon

If you go to
http://api.drupal.org/api/drupal/core!modules!system!system.install/group/updates-7.x-to-8.x/8
You will only see 3 update functions from system.install. However, there are quite a few other update functions in node.install, comment.install, locale.install, block.install, and user.install that should be part of this group.

The problem is that the group name has a - (hyphen) in it. This works for @defgroup, but the regular expression for @addtogroup is missing - in it, so it doesn't match and these functions are not added to the group. @addtogroup is working fine for groups that don't have a - in their name.

So we need to fix this (super simple fix in api_save_documentation() ).