R1:0abf29765e05

Make Phriction diff-of-changes view draft-aware and clarify some language

Summary:
Ref T13077. Ref T13197. See PHI840.

- In the "History > Diff/Compare" view, the button language wasn't draft-aware.
- Revise language to avoid the word "Revert", since this can be ambiguous.
- "Edit this page, starting with an older version of the text" is now "Edit Older|Current|Draft Version X".
- "Mark this older version of the page as the current published version" is now "Publish Older Version".
- Let…