Consistency pass to clean up choice/option language in question types

In `form-question-types` sometimes we say `choice` sometimes we say `option`. It'd be nice if we used consistent language here. I'd propose we default to `choice` and only use `option` if `choice` is awkward.

Search the documentation for the `form-question-types` section and review each use of `choice` and `option`. Standardize the wording to `choice` where it is natural, retaining `option` only where `choice` is awkward; done means the section uses consistent terminology.

Written by the indexing model from the issue text.