wmaker: Updated Dutch translation against changes in Info Panel

Only the 'msgid' was updated, to make sure gettext can still find
the old translation, but I am not fluent in Dutch so I can't do
better for the translated string.

po/nl.po

@@ -392,7 +392,7 @@ msgid "Total memory allocated: %i kB (in use: %i kB).\n"
 msgstr "Toegewezen geheugen: %i kB (gebruikt: %i kB).\n"
 
 #: ../src/dialog.c:1282
-msgid "Supported image formats: "
+msgid "Image formats: "
 msgstr "Ondersteunde afb.: "
 
 #: ../src/dialog.c:1292