Add test demonstrating how trivia is handled

[CyrusNajmabadi]

No description provided.

[sharwell]

It looks like the fixed code is missing a trailing comma in two cases.

[sharwell]

Suggested change

	new int[] { 2 }
	new int[] { 2 },

[sharwell]

Suggested change

	[2]
	[2],

[CyrusNajmabadi]

currently our features do not add a trailing comma, unless they're adding to an existing initializer that already had one.

I'm open to updating this decision and adding trailing commas in more places. However, i would like to do that outside of this PR.

@sharwell if we did go this route, would you be ok with these rules:

1. if we are adding to an existing collection-initializer/expression, we will have a trailing comma or not, depending on what the original code had.
2. If we are creating a new collection initializer/expression, and it all will be single-line, then we do not add a trailing comma.
3. If we are creating a new collection initializer/expression and there would be multiple elements, we place a comma after the last one.

If that fits what you want, i can make a followup PR to encode those rules.

Thanks!

[sharwell]

Yes, those are exactly the expected rules. I believe we settled on them in an earlier discussion.
#54859 (comment)

We should prioritize that work, as the current refactoring produces code which is problematic for maintainability.

[CyrusNajmabadi]

We should prioritize that work, as the current refactoring produces code which is problematic for maintainability.

Sure. I'll do tomorrow.

[CyrusNajmabadi]

@akhera99 @sharwell for approval.