- prefer `role=checkbox` over `input[type=checkbox]`
- prefer `#id` over `input[type=checkbox]` and `role=checkbox`
- prefer `text=foo` over `internal:has-text=foo`
- ignore `none` and `presentation` roles
- remove non-strict support
- Rename internal selectors `has`, `control` and `attr` to
`internal:has`, `internal:control` and `internal:attr`.
- Fix `getByLabel()` to respect strictness, by introducing
`internal:label` selector.
- Move tests essential for ports to `selectors-by.spec`.