[ENHANCEMENT] Add the old Ctrl+F6 keyboard shortcut to open the password hasher

[NintendoManiac64]

The classic XUL extension includes a Ctrl+F6 keyboard shortcut to open the password hasher, but this Webextension-API version seems to lack this keyboard shortcut.

Therefore, I'm suggesting that it be implemented.

　

If you need an easy way to reference the behavior of the classic XUL extension, it can still be installed and used in the portable version of Pale Moon:

• https://www.palemoon.org/download.shtml#Portable_versions

Also, the classic XUL extension itself can be accessed from archive.org (click the Download Anyway link):

• https://web.archive.org/web/20181009222125/https://addons.mozilla.org/en-US/firefox/addon/password-hasher/