diff.c: add dimming to moved line detection

Any lines inside a moved block of code are not interesting. Boundaries
of blocks are only interesting if they are next to another block of moved
code.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/color.h b/color.h
index 9062765..fd2b688 100644
--- a/color.h
+++ b/color.h
@@ -42,6 +42,8 @@ struct strbuf;
 #define GIT_COLOR_BG_BLUE	"\033[44m"
 #define GIT_COLOR_BG_MAGENTA	"\033[45m"
 #define GIT_COLOR_BG_CYAN	"\033[46m"
+#define GIT_COLOR_FAINT		"\033[2m"
+#define GIT_COLOR_FAINT_ITALIC	"\033[2;3m"
 
 /* A special value meaning "no color selected" */
 #define GIT_COLOR_NIL "NIL"