Add (temporary) Swedish localizations for the page_landmark/`loadin…

…g` strings (PR 13118 follow-up)

I'm adding these temporary l10n strings, so that I don't have to stare at a bunch of warning messages in the web-console when using the development viewer.

l10n/sv-SE/viewer.properties

@@ -154,8 +154,8 @@ findbar.title=Sök i dokument
 findbar_label=Sök
 
 additional_layers=Ytterligare lager
-# LOCALIZATION NOTE (page_canvas): "{{page}}" will be replaced by the page number.
-page_canvas=Sida {{page}}
+# LOCALIZATION NOTE (page_landmark): "{{page}}" will be replaced by the page number.
+page_landmark=Sida {{page}}
 # Thumbnails panel item (tooltip and alt text for images)
 # LOCALIZATION NOTE (thumb_page_title): "{{page}}" will be replaced by the page
 # number.
@@ -228,6 +228,7 @@ page_scale_actual=Verklig storlek
 page_scale_percent={{scale}}%
 
 # Loading indicator messages
+loading=Laddar…
 loading_error=Ett fel uppstod vid laddning av PDF-filen.
 invalid_file_error=Ogiltig eller korrupt PDF-fil.
 missing_file_error=Saknad PDF-fil.