There's a very clear explanation with examples of using --onto which is
currently buried in the very long DESCRIPTION section. This moves it to
its own section, so that we can reference the explanation from the
`--onto` option by name.
Signed-off-by: Julia Evans <julia@jvns.ca>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
D---E---A'---F master
------------
+TRANSPLANTING A TOPIC BRANCH WITH --ONTO
+----------------------------------------
+
Here is how you would transplant a topic branch based on one
branch to another, to pretend that you forked the topic branch
from the latter branch, using `rebase --onto`.
merge base of A and B if there is exactly one merge base. You can
leave out at most one of A and B, in which case it defaults to HEAD.
+See TRANSPLANTING A TOPIC BRANCH WITH --ONTO above for examples.
+
--keep-base::
Set the starting point at which to create the new commits to the
merge base of `<upstream>` and `<branch>`. Running