Sort suggestions by match index, then alphabetically

[kimsey0]

Implements suggestion from #12 (comment)

[jonsequitur]

This is a nice solution to #12. Thanks, @kimsey0!

Could you add a unit test that demonstrates the behavior in SuggestionTests? (The tests there currently avoid asserting on the order of the suggestions (e.g. by using BeEquivalentTo), since this wasn't locked down. We have a BeEquivalentSequenceTo extension method which is a convenience for strict ordering.)

[kimsey0]

Sure! Would you like the existing tests to be changed to BeEquivalentSequenceTo too, or just some new tests?

[jonsequitur]

It's good to just add a test. The existing tests are intentionally unconcerned with suggestion order.

[kimsey0]

I've added two tests of suggestions for subcommands, one with text to match and one without. Is this sufficient? I was a bit unsure about the naming, since SuggestionTests seems to contain both Noun_Sentence and Sentence style test names.

[jonsequitur]

This looks great. Thanks, @kimsey0!

[kimsey0]

Thank you!