fsck: rename objects-related fsck error functions

fsck: rename objects-related fsck error functions

The names of objects-related fsck error functions are generic. It's OK
when there is only object database check. However, we are going to
introduce refs database check report function. To avoid ambiguity,
rename object-related fsck error functions to explicitly indicate these
functions are used to report objects-related messages.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>