T6883, Button to save document in legalpad should say "Save Document" instead of "Edit Document"

Summary: Fixes T6883, Legalpad action button on edit document page should say "Save Document" instead of "Edit Document"

Test Plan: Open Legalpad, open existing document, blue action button should say "Save Document"

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T6883

Differential Revision: https://secure.phabricator.com/D11291