chainlint: reduce annotation noise-factor

When chainlint detects a problem in a test definition, it highlights the
offending code with a "?!...?!" annotation. The rather curious "?!"
decoration was chosen to draw the reader's attention to the problem area
and to act as a good "needle" when using the terminal's search feature
to "jump" to the next problem.

Later, chainlint learned to color its output when sent to a terminal.
Problem annotations are colored with a red background which stands out
well from surrounding text, thus easily draws the reader's attention.
Together with the preceding change which gave all problem annotations a
uniform "LINT:" prefix, the noisy "?!" decoration has become superfluous
as a search "needle" so omit it when output is colored.

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

Author: sunshineco

t/chainlint.pl

@@ -651,6 +651,7 @@ sub check_test {
 	$self->{nerrs} += @$problems;
 	return unless $emit_all || @$problems;
 	my $c = main::fd_colors(1);
+	my ($erropen, $errclose) = -t 1 ? ("$c->{rev}$c->{red}", $c->{reset}) : ('?!', '?!');
 	my $start = 0;
 	my $checked = '';
 	for (sort {$a->[1]->[2] <=> $b->[1]->[2]} @$problems) {
@@ -659,7 +660,7 @@ sub check_test {
 		my $err = format_problem($label);
 		$checked .= substr($body, $start, $pos - $start);
 		$checked .= ' ' unless $checked =~ /\s$/;
-		$checked .= "$c->{rev}$c->{red}?!LINT: $err?!$c->{reset}";
+		$checked .= "${erropen}LINT: $err$errclose";
 		$checked .= ' ' unless $pos >= length($body) ||
 		    substr($body, $pos, 1) =~ /^\s/;
 		$start = $pos;

t/test-lib.sh

@@ -1606,7 +1606,7 @@ if test "${GIT_TEST_CHAIN_LINT:-1}" != 0 &&
    test "${GIT_TEST_EXT_CHAIN_LINT:-1}" != 0
 then
 	"$PERL_PATH" "$TEST_DIRECTORY/chainlint.pl" "$0" ||
-		BUG "lint error (see '?!...!? annotations above)"
+		BUG "lint error (see 'LINT' annotations above)"
 fi
 
 # Last-minute variable setup