In addition to the trivial search-and-replace performed over the course
of the previous three commits, there is one test in t5411 that depends
on the length of the default branch name.
Adjust it and use `main` as the default branch name in this test.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>