Make link hints show appropriate and correct number of letters

With this as my Vimari settings:

{
  "excludedUrls": "",
  "linkHintCharacters": "werafjkl:",
  "detectByCursorStyle": false,
  "scrollSize": 150,
  "openTabUrl": "",
  "modifier": "",
  "smoothScroll": true,
  "scrollDuration": 25,
  "bindings": {
      "hintToggle": "f",
      "newTabHintToggle": "shift+f",
      "scrollUp": "k",
      "scrollDown": "j",
      "scrollLeft": "h",
      "scrollRight": "l",
      "goToPageTop": "g g",
      "goToPageBottom": "shift+g",
      "goToFirstInput": ":",
      "goBack": "shift+j",
      "goForward": "shift+k",
      "reload": "r",
      "tabBack": "a",
      "tabForward": "w",
      "closeTab": "e",
  }
}

I often encounter a bug where a link hint that ends with a w will trigger tabForward after going to the link hint as it is supposed to do.

[nbelzer]

I feel like filtering out the bindings is not such a great solution. It limits users to keybindings they haven’t assigned yet while we are already blocking the Vimari bindings in link-hint-mode. Perhaps we could filter out those bindings for the last character in the link hints.

So if there are more link hints needed than all 2 letter combinations. Show all for the 2 letter combos and then do remaining combos with 3 letters. Same applies for 1 and 2 letter.

Changing the link hint behaviour to work like this would require more significant changes to the link-hint code. This might be worth investigating if we cannot get a Vimium port to Safari. However for now I believe we should go with the second option (to require all characters in the hint to be typed) as this is most inline with what the user expects when presented with the link hints.

[nbelzer]

While the merged PR #191 uses the suggested solution, the larger problem of incorrectly sized link hints remains.