Revert "[clang-tidy] Use default to initialize constructors"

This reverts commit bf40ea8816.

src/Lexer.cpp

@@ -50,7 +50,9 @@ Lexer::Lexer (const std::string& text)
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-Lexer::~Lexer () = default;
+Lexer::~Lexer ()
+{
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 // When a Lexer object is constructed with a string, this method walks through