Use ≡ for the hamburguer menu in the onboarding
reported by translator (thanks AO!):
In chrome/locale/en-US/browserOnboarding.properties we could use the char ≡ instead of = to refer to the hamburguer menu.
here a branch: https://dip.torproject.org/emmapeel/torbutton/commits/hamburguer
and the commit: https://dip.torproject.org/emmapeel/torbutton/commit/357dc2f1735e16252f6ea6e61b385182a2929f70