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/sendf.h

@@ -55,7 +55,7 @@ struct Curl_cwriter;
 struct Curl_easy;
 
 /**
- * Write `len` bytes at `prt` to the client. `type` indicates what
+ * Write `len` bytes at `buf` to the client. `type` indicates what
  * kind of data is being written.
  */
 CURLcode Curl_client_write(struct Curl_easy *data, int type, const char *buf,