The registerLinkMatcher() should support returning the row and column position of the link so it can be used for position the hover message. Related to microsoft/vscode#77964.

For VSCode, I believe this is needed in order to match the terminal link experience (the popup starts where the link starts) to the rest of the editor. Currently, there is no way to get the position of the link, and the hover position is just the mouse position, which is inconsistent.