For Ctrl-[, also require NOT Alt
For Ctrl-[, also require NOT Alt

See #1906.

It is not obvious that this is in fact correct.  In particular, it's not
clear how `Ctrl-[` should work on Mac keyboards.

mrmr1993/vimium,philc/vimium,willsALMANJ/vimium,decaffeinate-examples/vimium,willsALMANJ/vimium,mrmr1993/vimium,poacher2k/vimium,mrmr1993/vimium,smblott-github/vimium,smblott-github/vimium,decaffeinate-examples/vimium,philc/vimium,decaffeinate-examples/vimium,poacher2k/vimium,willsALMANJ/vimium,gdh1995/vimium,gdh1995/vimium,smblott-github/vimium,poacher2k/vimium,gdh1995/vimium,philc/vimium