fixed character encoding bug

src/main/java/de/srsoftware/widerhall/web/TemplateServlet.java

@@ -8,6 +8,7 @@ import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletResponse;
 import java.io.File;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.Map;
 
@@ -40,6 +41,7 @@ public abstract class TemplateServlet extends HttpServlet {
         var template = templates.getInstanceOf(path);
         if (template != null){
             try {
+                resp.setCharacterEncoding("UTF-8");
                 template.add("data",data);
                 resp.getWriter().println(template.render());
                 return null;