Date and time input types

Form field widgets to easily allow users to enter a date, time or both, generally by using a calendar/time input widget. Refers to supporting the following input types: `date`, `time`, `datetime-local`, `month` & `week`.

css selector: `:placeholder-shown`: support on non-`type="text"` elements (such as `type="number"` or `type="time"`)

html element: input: `type="time"`