there is no ś in HTML

* lisp/org-exp.el (org-export-language-setup): Fix Polish entries.

Hello.

There is no such named entity as ś. If you want to be 7bit clean
then use ś (or decimal ś).

lisp/org-exp.el

@@ -181,7 +181,7 @@ This option can also be set with the +OPTIONS line, e.g. \"-:nil\"."
     ("no" "Forfatter"  "Dato"  "Innhold" "Fotnoter")
     ("nb" "Forfatter"  "Dato"  "Innhold" "Fotnoter")  ;; nb = Norsk (bokm.l)
     ("nn" "Forfattar"  "Dato"  "Innhald" "Fotnotar")  ;; nn = Norsk (nynorsk)
-    ("pl" "Autor"      "Data" "Spis treści"  "Przypis")
+    ("pl" "Autor"      "Data" "Spis treści"  "Przypis")
     ("sv" "Författare" "Datum" "Innehåll" "Fotnoter"))
   "Terms used in export text, translated to different languages.
 Use the variable `org-export-default-language' to set the language,