(i18n-js) alias i18n:extract to i18n:generate
(i18n-js) alias i18n:extract to i18n:generate

for backwards compat until we upgrade all the callsites to use
i18n:extract

refs FOO-2801
flag = none

~ test plan ~

you can call "rake i18n:generate" to do what "rake i18n:extract" does

Change-Id: I0a4cd9a1fe8273aad0a570c3dc5beaf61bc8554c
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/294619
Reviewed-by: Jacob Burroughs <8ecea6e385af5cf9f53123f5ca17fb5fd6a6d4b2@instructure.com>
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
QA-Review: Ahmad Amireh <a53a33601b8dd9d06ae9e50f1f30fbe957aba866@instructure.com>
Product-Review: Ahmad Amireh <a53a33601b8dd9d06ae9e50f1f30fbe957aba866@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms