Add ApiOption overloads to IIssuesClient and IObservableIssuesClient

[shiftkey]

Fixes #1158

This is a big one, so I'm going through it as slowly and methodically as possible:

• add new methods
• update impacted unit tests
• add new unit tests wherever appropriate
• add new integration tests wherever appropriate
• correct references in xml-docs

[ryangribble]

really minor nitpick but the equivalent code in other unit tests in this file are all on one line, while these ones are indented/split...

[shiftkey]

👍 just my 80-chars-per-line OCD acting up. I'll undo this.

[ryangribble]

it's hard to review these changes, but Im grasping at straws to find anything major here 😀

[shiftkey]

@ryangribble thanks for the 👀, I think there's a bunch of new test coverage here I can do but given how many overloads there are I'm trying to keep this as focused as possible.

[shiftkey]

I also took some time out in 1b2d009 to document the return values from the API. Let me know if you have any feedback on the words.

[shiftkey]

Lots of the pagination endpoints here require you to have org access, so rather than getting too bogged down in pagination I'm going to skip those tests.

[ryangribble]

I also took some time out in 1b2d009 to document the return values from the API. Let me know if you have any feedback on the words.

I noticed you are using <seealso cref="" when most other cases in the code base are using <see cref="" - is there any reason for using one over the other?

The wording sounds reasonable although I wonder whether the effort involved to doc all return values is worth it, since they are pretty self evident... and it then sorta means we have to go and add them to allll the rest of the codebase. I guess the same could be said for doccing most parameters in general though and if we didnt do it then we would have no doc anywhere. Does this mean you intend us to start the process of docing return value on everything from now on?

[shiftkey]

Can I get a 👍 here before I close this out?