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/curl_config-cmake.h.in

@@ -725,13 +725,13 @@ ${SIZEOF_TIME_T_CODE}
    automatically */
 #cmakedefine CURL_DISABLE_OPENSSL_AUTO_LOAD_CONFIG 1
 
-/* to enable NGHTTP2  */
+/* to enable NGHTTP2 */
 #cmakedefine USE_NGHTTP2 1
 
 /* to enable NGTCP2 */
 #cmakedefine USE_NGTCP2 1
 
-/* to enable NGHTTP3  */
+/* to enable NGHTTP3 */
 #cmakedefine USE_NGHTTP3 1
 
 /* to enable quiche */
@@ -743,13 +743,13 @@ ${SIZEOF_TIME_T_CODE}
 /* Define to 1 if you have the quiche_conn_set_qlog_fd function. */
 #cmakedefine HAVE_QUICHE_CONN_SET_QLOG_FD 1
 
-/* if Unix domain sockets are enabled  */
+/* if Unix domain sockets are enabled */
 #cmakedefine USE_UNIX_SOCKETS 1
 
 /* to enable SSPI support */
 #cmakedefine USE_WINDOWS_SSPI 1
 
-/* to enable Windows SSL  */
+/* to enable Windows SSL */
 #cmakedefine USE_SCHANNEL 1
 
 /* if Watt-32 is in use */