sync: If a test case was added that reimplements another case, print the reimplemented UUID as well

[cmccandless]

Related to #44

For this example, assume that the grains case 10f45584-2fc3-4875-8ec6-666065d1163b reimplements another case b4bacc5a-3c12-43b6-ab17-d5ec78d70a15

As of configlet 4.0.0-beta.5:

$ configlet sync --tests --verbosity=detailed
[...]
[warn] grains: missing 2 test cases
       - grains on square 3 (10f45584-2fc3-4875-8ec6-666065d1163b)

Proposed

Put reimplemented case description and UUID on following line (for human readability)

$ configlet sync --tests --verbosity=detailed
[...]
[warn] grains: missing 2 test cases
       - grains on square 3 (10f45584-2fc3-4875-8ec6-666065d1163b)
         - reimplements: square 3 grains (b4bacc5a-3c12-43b6-ab17-d5ec78d70a15)

Alternative notation

Put reimplemented case UUID on same line (simpler to parse for scripts)

$ configlet sync --tests --verbosity=detailed
[...]
[warn] grains: missing 2 test cases
       - grains on square 3 (10f45584-2fc3-4875-8ec6-666065d1163b -> b4bacc5a-3c12-43b6-ab17-d5ec78d70a15)