Merge branch 'sb/range-diff-colors'

The color output support for recently introduced "range-diff"
command got tweaked a bit.

* sb/range-diff-colors:
  range-diff: indent special lines as context
  range-diff: make use of different output indicators
  diff.c: add --output-indicator-{new, old, context}
  diff.c: rewrite emit_line_0 more understandably
  diff.c: omit check for line prefix in emit_line_0
  diff: use emit_line_0 once per line
  diff.c: add set_sign to emit_line_0
  diff.c: reorder arguments for emit_line_ws_markup
  diff.c: simplify caller of emit_line_0
  t3206: add color test for range-diff --dual-color
  test_decode_color: understand FAINT and ITALIC

t/test-lib-functions.sh

@@ -42,6 +42,8 @@ test_decode_color () {
 		function name(n) {
 			if (n == 0) return "RESET";
 			if (n == 1) return "BOLD";
+			if (n == 2) return "FAINT";
+			if (n == 3) return "ITALIC";
 			if (n == 7) return "REVERSE";
 			if (n == 30) return "BLACK";
 			if (n == 31) return "RED";