Add look up selection when there is a selection in macOS. Fixes #1627

[jmalonzo]

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Ran git rebase -i to squash commits if needed.

[bbondy]

++ thanks! Eventually we need to make locale.translation take arguments as well so we can localize them properly but since we don't have that yet, what you did is fine.