Add option to allow createHint to work in blacklisted pages

[Rui-L]

I am wondering if you could allow createHint to work for blacklisted pages. Most pages in blacklist provides some their own shortcut systems, but none of them work perfectly for all situations, so I still want to have "f" to work in that case. For example, when using Gmail, there is no builtin shortcut to go gmail Settings, no shortcut to go to Snoozed, and the shortcut for "Compose" is fixed to pop-out a window which will always be blocked by Safari, regardless of Safari settings. So it's still nice if I can allow "f" to work in this case. Hope you consider! Thanks.