Make variable name clearer

diff-so-fancy

@@ -110,13 +110,13 @@ my @lines;
 local $DiffHighlight::line_cb = sub {
 	push(@lines,@_);
 
-	my $last_line = $lines[-1];
+	my $prev_line = $lines[-1];
 
 	# Buffer X lines before we try and output anything
 	# Also make sure we're sending enough data to d-s-f to do it's magic.
 	# Certain things require a look-ahead line or two to function so
 	# we make sure we don't break on those sections prematurely
-	if (@lines > 24 && ($last_line !~ /^${ansi_color_regex}(---|index|old mode|similarity index|rename (from|to))/)) {
+	if (@lines > 24 && ($prev_line !~ /^${ansi_color_regex}(---|index|old mode|similarity index|rename (from|to))/)) {
 		do_dsf_stuff(\@lines);
 		@lines = ();
 	}