don't break if object doesn't support to_s (e.g. BasicObject)

Author: denofevil

lib/ruby-debug-ide/xml_printer.rb

@@ -401,7 +401,11 @@ def build_compact_value_attr(value, value_str)
     end
 
     def safe_to_string(value)
-      str = value.to_s
+      begin
+        str = value.to_s
+      rescue NoMethodError
+        str = "(Object doesn't support #to_s)"
+      end
       return str unless str.nil?
 
       string_io = StringIO.new