feat: add c++ wfassoc wrapper

wfassoc-cdylib/codegen/wfassoc.h

@@ -4,12 +4,12 @@
  *
  * This header provides a C-compatible API for managing Windows file associations,
  * including schema creation, program registration, and extension management.
- * The API is designed to work with both C and C++ compilers.
+ * The API is designed to at least work with both C99 and C++17 compilers.
  */
 
 #pragma once
-#ifndef __WFASSOC_H__
-#define __WFASSOC_H__
+#ifndef WFASSOC_H_
+#define WFASSOC_H_
 
 #ifdef __cplusplus
 #include <cstddef>
@@ -537,4 +537,4 @@ bool WFExtGetDottedInner(Token in_ext, CStyleString *out_inner);
 }  // namespace wfassoc
 #endif  // __cplusplus
 
-#endif  // __WFASSOC_H__
+#endif  // WFASSOC_H_