*.h: move some *_INIT to designated initializers
Move various *_INIT macros to use designated initializers. This helps readability. I've only picked those leftover macros that were not touched by another in-flight series of mine which changed others, but also how initialization was done. In the case of SUBMODULE_ALTERNATE_SETUP_INIT I've left an explicit initialization of "error_mode", even though SUBMODULE_ALTERNATE_ERROR_IGNORE itself is defined as "0". Let's not peek under the hood and assume that enum fields we know the value of will stay at "0". The change to "TESTSUITE_INIT" in "t/helper/test-run-command.c" was part of an earlier on-list version[1] of c90be786da9 (test-tool run-command: fix flip-flop init pattern, 2021-09-11). 1. https://lore.kernel.org/git/patch-1.1-0aa4523ab6e-20210909T130849Z-avarab@gmail.com/ Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>