Add support for functions.* (complete) methods

[misscoded]

Summary

Adds support for the following functions.* methods:

functions.completeError
functions.completeSuccess

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[seratch]

I believe this paramter is required (our work-in-progress document says so too)

[misscoded]

You're probably right. I'll retest to be doubly certain and remove optionality upon confirmation.

[misscoded]

Although, to be fair, outputs may not be passed on so it's odd to require them!

[seratch]

if i remember correctly, an empty outputs object might be required even when the function does not have any required output_parameters in its definition.

[seratch]

meaning the server-side can return an error code to such a request

[filmaj]

Indeed, on the deno side, outputs is a required property (see this code).

[filmaj]

Thanks for tackling this! Yep, Kaz is right, outputs is required when marking a function as complete.

[filmaj]

Indeed, on the deno side, outputs is a required property (see this code).

[filmaj]

[seratch]

Thanks for working on this; now this looks good to me 👍