Merges are often treated as special case objects so tell users that
they are not special here.
Signed-off-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Unless `-f` is given, the 'replace' reference must not yet exist.
There is no other restriction on the replaced and replacement objects.
+Merge commits can be replaced by non-merge commits and vice versa.
Replacement references will be used by default by all Git commands
except those doing reachability traversal (prune, pack transfer and