t / chainlint / command-substitution.expecton commit diff: add an internal option to dual-color diffs of diffs (f7c3b4e)
   1(
   2        foo &&
   3        bar=$(gobble) &&
   4        baz
   5>) &&
   6(
   7?!AMP?! bar=$(gobble blocks)
   8        baz
   9>)