LibHTML: Hide debugging output unless HTML_DEBUG is defined

Author: https://github.com/bugaevc
Commit: 6491493e26
Pull-request: https://github.com/SerenityOS/serenity/pull/609
Reviewed-by: https://github.com/awesomekling ✅

Libraries/LibHTML/CSS/StyleResolver.cpp

@@ -45,10 +45,14 @@ NonnullRefPtrVector<StyleRule> StyleResolver::collect_matching_rules(const Eleme
             }
         }
     }
+
+#ifdef HTML_DEBUG
     printf("Rules matching Element{%p}\n", &element);
     for (auto& rule : matching_rules) {
         dump_rule(rule);
     }
+#endif
+
     return matching_rules;
 }