merge: move doc to ll-merge.h
Move the related documentation from Documentation/technical/api-merge.txt
to ll-merge.h as it's easier for the developers to find the usage
information beside the code instead of looking for it in another doc file.
Only the ll-merge related doc is removed from
documentation/technical/api-merge.txt because this information will be
redundant and it'll be hard to keep it up to date and synchronized with
the documentation in ll-merge.h.
Signed-off-by: Heba Waly <heba.waly@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>