Remove scattered links to "Support" document

Summary:
I'm going to do some version of D13941. Clean up extra links to the old document first.

These were just randomly links from various places that we no longer really want feedback on and/or are now better covered by other documents.

Test Plan:

• grep
• Reviewed Config/Welcome screen.
• Reviewed uri.allowed-editor-protocols.

Reviewers: chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D14303