TypeScript typing thenResolve takes variable args

[miyu]

For consistency with thenReturn - no changes to library necessary.

[searls]

Build failure was erroneous. Restarted.

@duluca will merge if you approve change

[duluca]

It'd be great if this PR is updated once #260 is merged, so there's a valid CI run against this change.

TODO:
[ ] Update from master once #260 is merged
[ ] Add a line to test.ts that exercises the spread feature
[ ] Update this PR and make sure CI checks pass

[searls]

ok @duluca, #260 (nay #259) is now merged, so this should be doable now.

[miyu]

Merged #260, changed test.ts. I figure if the spread case is covered the one-arg case is covered?

[duluca]

@miyu I concur

[searls]

Stupid Q: does thenResolve() actually support multiple promises? I don't think we have a test for this in test/src/when-test.coffee. Can you validate for me?

[miyu]

I'm using thenResolve(a, b) in my own tests.

[searls]

Sure enough. I added some tests for this to ensure I don't break you in #263