Libraries: Use default constructors/destructors in LibCpp

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#cother-other-default-operation-rules

"The compiler is more likely to get the default semantics right and
you cannot implement these functions better than the compiler."

Userland/Libraries/LibCpp/SyntaxHighlighter.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, the SerenityOS developers.
+ * Copyright (c) 2020-2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -98,8 +98,4 @@ bool SyntaxHighlighter::token_types_equal(u64 token1, u64 token2) const
     return static_cast<Cpp::Token::Type>(token1) == static_cast<Cpp::Token::Type>(token2);
 }
 
-SyntaxHighlighter::~SyntaxHighlighter()
-{
-}
-
 }