check if block given before yield in xml's print_element

Author: viuginick1

lib/ruby-debug-ide/xml_printer.rb

@@ -442,7 +442,7 @@ def print_load_result(file, exception = nil)
     def print_element(name)
       print("<#{name}>")
       begin
-        yield
+        yield if block_given?
       ensure
         print("</#{name}>")
       end