feat: extended hints support

[ueokande]

Support extended hints

This pull request adds support for extended hints. Extended hints are originally implemented in vimperator-labs. This change supports the following extended hints:

• ;i: open an image in the current tab
• ;I: open an image in a new tab
• ;y: copy a link URL to the clipboard
• ;Y: copy a link text to the clipboard
• ;v: open a source URL in the current tab
• ;V: open a source URL in a new tab
• ;o: open a URL in the current tab
• ;t: open a URL in a new tab
• ;w: open a URL in a new window
• ;O: open the console with :open and the selected URL
• ;T: open the console with :tabopen and the selected URL
• ;W: open the console with :winopen and the selected URL

It also rename the following command in key maps:

-    "f": { "type": "follow.start", "newTab": false },
-    "F": { "type": "follow.start", "newTab": true, "background": false },
+    "f": { "type": "hint.quick", "newTab": false },
+    "F": { "type": "hint.quick", "newTab": true, "background": false },