Reviewed all i18n-hint comments...

... Moved many misplaced ones, which msgfmt would not have extracted into
audacity.pot.

Duplicated some of them, to appear with related but distinct msgids.

Added a few new comments.

Deleted one that was no longer needed in ProjectManager.cpp.

src/HistoryWindow.cpp

@@ -391,9 +391,9 @@ AttachedItem sAttachment{ wxT("View/Windows"),
    // FOR REDESIGN,
    // clearly there are some limitations with the flags/mask bitmaps.
 
+   ( FinderScope{ findCommandHandler },
    /* i18n-hint: Clicking this menu item shows the various editing steps
       that have been taken.*/
-   ( FinderScope{ findCommandHandler },
       Command( wxT("UndoHistory"), XXO("&History..."), &Handler::OnHistory,
          AudioIONotBusyFlag() ) )
 };