tidy-up: miscellaneous

- vms/curlmsg_vms.h: delete unused/commented code.
- vtls/schannel_verify: sort includes.
- typecheck-gcc.h: fix indent and alignment.
- lib/config-win32.h: drop idle `#undef`.
- spacecheck: check for stray empty lines before after curly braces.
- make literals more readable: 1048576 -> 1024 * 1024
- scope variables.
- use ISO date in a comment.
- drop redundant parentheses.
- drop empty comments.
- unfold lines.
- duplicate/stray spaces in comments.
- fix indent, whitespace, minor typos.

Closes #20690

lib/system_win32.c

@@ -45,7 +45,7 @@ CURLcode Curl_win32_init(long flags)
 
     if(res)
       /* Tell the user that we could not find a usable */
-      /* winsock.dll.     */
+      /* winsock.dll. */
       return CURLE_FAILED_INIT;
 
     /* Confirm that the Windows Sockets DLL supports what we need.*/