Provide a hover for the given position and document. Multiple hovers at the same position will be merged by the editor. A hover can have a range which defaults to the word range at the position when omitted.
The document in which the command was invoked.
The position at which the command was invoked.
A cancellation token.
A hover or a thenable that resolves to such. The lack of a result can be
signaled by returning undefined or null.
The hover provider interface defines the contract between extensions and the hover-feature.