R1:3d44208e4f65

Clarify that "account.editable" no longer extends to profile pictures

Summary: Fixes T12216. I'd like to remove this option eventually, but just narrow its scope in the config description for now.

Test Plan: Read config description.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T12216

Differential Revision: https://secure.phabricator.com/D17317