Auto merge of #86211 - tlyu:option-result-overviews, r=joshtriplett

Auto merge of #86211 - tlyu:option-result-overviews, r=joshtriplett

create method overview docs for core::option and core::result

The `Option` and `Result` types have large lists of methods. They each could use an overview page of methods grouped by category. These proposed overviews include "truth tables" for the underappreciated boolean operators/combinators of these types. The methods are already somewhat categorized in the source, but some logical groupings are broken up by the necessities of putting related methods in different `impl` blocks, for example.

This is based on #86209, but those are small changes and unlikely to conflict.