Sync SDL3 wiki -> header

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include/SDL3/SDL_stdinc.h

@@ -3023,7 +3023,7 @@ extern SDL_DECLSPEC long SDLCALL SDL_wcstol(const wchar_t *str, wchar_t **endp,
  * If you need the length of a UTF-8 string, consider using SDL_utf8strlen().
  *
  * \param str The null-terminated string to read. Must not be NULL.
- * \returns the length (in bytes, excluding the null terminator) of `src`.
+ * \returns the length (in bytes, excluding the null terminator) of `str`.
  *
  * \threadsafety It is safe to call this function from any thread.
  *