[prism] Fix comment check for expression-led call chains

[reese]

I was writing the test cases I promised in #770 but found several edge cases that either formatted incorrectly or were simply not idempotent over multiple formats. This PR adds a bunch of fixtures around this particular scenario (call chains starting with expressions and comments between/around the first caller). Ripper has almost the same behavior, though it has the same idempotency issues that this intends to resolve, so I've made this a Prism-only test case.

The specific change in logic is that previously we were only checking for comments between the end of the leading expression and the dot-operator, like this:

[
  foo
] # a comment goes here!
  .freeze

But really, the check is trying to look for any comment that would actually render in that space. This means that in the comment above, we actually don't care about that comment (because it will always get shifted inside the closing brace), but it also means we do care about comments that would render there, such as trailing comments that might be outside of the call chain proper, such as

[
  foo
]
  .freeze # Don't forget about this one!