Fix divide by zero.
Fix divide by zero.

If text.length is 1, here, then we divide by `log 1` - which is zero.
So add one.

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