chainlint.sed: improve ?!AMP?! placement accuracy

chainlint.sed: improve ?!AMP?! placement accuracy

When chainlint.sed detects a broken &&-chain, it places an ?!AMP?!
annotation at the beginning of the line. However, this is an unusual
location for programmers accustomed to error messages (from compilers,
for instance) indicating the exact point of the problem. Therefore,
relocate the ?!AMP?! annotation to the end of the line in order to
better direct the programmer's attention to the source of the problem.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>