add section tooltip to discussions
add section tooltip to discussions

Fixes COMMS-992

Test Plan:
- go to any discussions show page
- notice the sections tooltip is there

Change-Id: I16611113502e25c73ca0f25c8f32c97b54be67e9
Reviewed-on: https://gerrit.instructure.com/144500
Reviewed-by: Landon Gilbert-Bland <60d9ff23682c863d36b48b4c32c5ce5f434d29c0@instructure.com>
Reviewed-by: Aaron Kc Hsu <089edc94045de3d9f5f372fb17706d21afcc259f@instructure.com>
QA-Review: Venk Natarajan <f9eab59b292314637a3c917fea4742741e36a19b@instructure.com>
Tested-by: Jenkins
Product-Review: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>

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