HackStudio: Abstract over syntax highlighter

Author: https://github.com/oriko1010
Commit: 137d68a2ae
Pull-request: https://github.com/SerenityOS/serenity/pull/1429
Reviewed-by: https://github.com/awesomekling

Libraries/LibGUI/CppSyntaxHighlighter.h

@@ -9,6 +9,9 @@ public:
     CppSyntaxHighlighter() {}
     virtual ~CppSyntaxHighlighter() override;
 
+    virtual bool is_identifier(void*) const override;
+    virtual bool is_navigatable(void*) const override;
+
     virtual SyntaxLanguage language() const override { return SyntaxLanguage::Cpp; }
     virtual void rehighlight() override;
     virtual void highlight_matching_token_pair() override;