[shotwell] Add translation context to some strings

[Jens Georg <jensgeorg src gnome org>]

commit c60cdd7beef71e5ea993d4cc7d8d744c6fcc7017
Author: Jens Georg <mail jensge org>
Date:   Sun May 29 18:43:19 2022 +0200

    Add translation context to some strings
    
    As pointed out by msgfmt

 src/Dialogs.vala   | 2 +-
 src/PhotoPage.vala | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/src/Dialogs.vala b/src/Dialogs.vala
index ee9aef9b..d123ca37 100644
--- a/src/Dialogs.vala
+++ b/src/Dialogs.vala
@@ -71,7 +71,7 @@ public File? choose_file(string current_file_basename) {
         current_export_dir = File.new_for_path(Environment.get_home_dir());
 
     string file_chooser_title = VideoReader.is_supported_video_filename(current_file_basename) ?
-        _("Export Video") : _("Export Photo");
+        _("Export Video") : GLib.dpgettext2 (null, "Dialog Title", "Export Photo");
         
     var chooser = new Gtk.FileChooserNative(file_chooser_title,
         AppWindow.get_instance(), Gtk.FileChooserAction.SAVE, Resources.SAVE_LABEL, Resources.CANCEL_LABEL);
diff --git a/src/PhotoPage.vala b/src/PhotoPage.vala
index 7b5e758f..4d21647d 100644
--- a/src/PhotoPage.vala
+++ b/src/PhotoPage.vala
@@ -2894,7 +2894,8 @@ public class LibraryPhotoPage : EditingHostPage {
         Gee.Collection<LibraryPhoto> photos = new Gee.ArrayList<LibraryPhoto>();
         photos.add(photo);
         
-        remove_from_app(photos, _("Remove From Library"), _("Removing Photo From Library"));
+        remove_from_app(photos, GLib.dpgettext2(null, "Dialog Title", "Remove From Library"),
+            GLib.dpgettext2(null, "Dialog Title", "Removing Photo From Library"));
     }
     
     private void on_move_to_trash() {        
@@ -3018,7 +3019,7 @@ public class LibraryPhotoPage : EditingHostPage {
         if (!has_photo())
             return;
         
-        ExportDialog export_dialog = new ExportDialog(_("Export Photo"));
+        ExportDialog export_dialog = new ExportDialog(GLib.dpgettext2(null, "Dialog Title", "Export Photo"));
         
         int scale;
         ScaleConstraint constraint;