Consider consolidating all link hints commands to one: LinkHints.activate

[philc]

Today we have several very similar link hints commands. Each one specifies an option to a core command.

To improve this and allow people to combine these orthogonal options together, we could move to one command, LinkHints.activate, which takes parameters to customize its behavior:

• action: open, focus, hover, copy
• destination/placement: current tab, new tab, new window
• multiple: i.e. open many at once; currently LinkHints.activateModeWithQueue
• focus on open: whether to switch immediately to the new tab
• incognito: whether the destination should be an incognito window

This would make it seamless to add in long-tail use cases for the link hints command, like opening a link in a new window rather than a new tab (#3450).

These are the historical reasons we have separate commands for each parameter:

1. We added each link hints variant one at a time over many years.
2. The ability to have user-specified options on Vimium commands was added much later.
3. The only way we expose documentation about commands is in the help dialog, which even today doesn't have a way of listing and explaining the various options that some commands accept. However, we're progressing the UX towards this capability. Now the help dialog shows if a user has added any options to commands they've bound; next is to implement a better UX for documenting all commands and their allowed options (see [RFC] Add a (painfully) minimal commands listing #2827 for inspiration).

Backwards compatibility: we can either migrate people's existing configurations at the time they are read, or we can indefinitely support e.g. LinkHints.activateModeToOpenInNewTab as an alias for LinkHints.activate destination=newTab.

Related: #1948.