Fixed #20826 -- Moved Manager.raw() and Manager._insert() to the QuerySet class.

[loic]

No description provided.

[mjtamlyn]

I'm definitely in favour of moving _insert, it's a silly place for it to be. As for raw - it's kinda confusing to have it on queryset because `qs.filter(foo='bar').raw('...') becomes possible but totally ignores the filter. I think this is why it was on the manager to start with.

That said I can understand why with the other changes it is helpful to be able to call raw from a QS. It just needs to be really well documented that it ignores everything else.

[loic]

@mjtamlyn: added a new commit with an update to the docs. The same could be said for create() and bulk_create() but I guess these two are less ambiguous.

[timgraham]

double `` here and next line

[timgraham]

merged in acd1d43

[loic]

Thanks for the merge!