fix misspell

module/src/main/java/pl/clarin/any2txt/Converter.java

@@ -93,7 +93,7 @@ public class Converter extends Worker {
                 try {
                     DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
                     DocumentBuilder loader = factory.newDocumentBuilder();
-                    ins.setEncoding("UTF-8");
+                    inS.setEncoding("UTF-8");
                     Document document = loader.parse(inS);
 
                     DocumentTraversal trav = (DocumentTraversal) document;