ox: add dictionary entry for numbered figures

* lisp/ox.el: (org-export-dictionary): Add "Figure %d:" entry
in the same manner with "Table %d:".

TINYCHANGE

lisp/ox.el

@@ -5266,6 +5266,9 @@ them."
     ("Figure"
      ("de" :default "Abbildung")
      ("es" :default "Figura"))
+    ("Figure %d:"
+     ("de" :default "Abbildung %d:")
+     ("es" :default "Figura %d:"))
     ("Footnotes"
      ("ca" :html "Peus de pàgina")
      ("cs" :default "Pozn\xe1mky pod carou")