Include shortened version of admin.site.register in admin docs
|Reported by:||Owned by:||nobody|
|Has patch:||no||Needs documentation:||no|
|Needs tests:||no||Patch needs improvement:||no|
While on #django in IRC, many people were unaware of the shortened version registering ModelAdmin classes with the admin. It would be nice to point this out in the docs. Apparently it is mentioned on the backwards incompatible page but not in the docs proper...