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

scripts/managen

@@ -529,7 +529,6 @@ sub render {
         my $qstr = $quote ? "q" : "";
         push @desc, "[".(1 + $level)."$qstr]$d" if(!$manpage);
         $header = 0;
-
     }
     if($finalblank) {
         print STDERR "$f:$line:1:ERROR: trailing blank line\n";