In a series of forks, allow later forks to be merged into top document
If you have top document
<- fork 1
<- fork 2
and fork 1
gets merged, fork 1
becomes frozen and now fork 2
can just publish. But it could also be merged into top document
. Or in fact continue to be rebased from top document
. Moreover, even before fork 1
is merged, fork 2
could be merged instead, making fork 1
obsolete (not sure what should be its status then).
So maybe we should allow controlling which document is an active parent document to be merged into (and rebased from).