Remove all product name literals in "pht()" in Arcanist

Summary:
Ref T13658. Remove all product name literals from "pht()" strings, by replacing them with generic text where that feels reasonably natural, or "PlatformSymbols" calls elsewhere.

These calls were identified with arc lint --everything after enabling the lint rule in D21763.

Test Plan: Read strings, ran "arc".

Maniphest Tasks: T13658

Differential Revision: https://secure.phabricator.com/D21764