Converting these pesky straight single/double quotes to curly

Summary: Wish I didn't miss these! Considering contributing to a markdown linter so this isn't so prevalent

Test Plan: n/a

Reviewers: atul, ashoat

Reviewed By: ashoat

Subscribers: ashoat, palys-swm, Adrian, karol-bisztyga, boristopalov

Differential Revision: https://phabricator.ashoat.com/D2689