tidy-up: miscellaneous

- curl_ntlm_core, smtp, schannel: fix comments.
- curl_setup.h: fix to undef before define.
- tool_doswin, server/sockfilt: reduce variables scopes.
- tool_doswin: drop an interim variable.
- windows: replace `SOCKET_ERROR` with `0` to align with rest of code.
- libssh2: rename variable to align with rest of code.
- gtls, unit1398: use `#if 0`.
- curl_trc.h, curlx/inet_ntop.h: add missing parentheses in macro
  expressions.
- ldap.c: set empty macro to `do {} while(0)`.
- examples/crawler: rename a non-CURLcode `result` variable.
- CURLINFO_TLS_SESSION: drop stray colon.
- add `const` to casts where missing.
- drop unnecessary parentheses.
- fix indent.
- quote style.
- comment style.
- whitespace, newlines, fold/unfold.

Closes #20554

tests/sshserver.pl

@@ -223,7 +223,7 @@ $logfile = "$logdir/sshserver.log";  # used by logmsg
 #***************************************************************************
 # Logging level for ssh server and client
 #
-my $loglevel = $debugprotocol?'DEBUG3':'DEBUG2';
+my $loglevel = $debugprotocol ? 'DEBUG3' : 'DEBUG2';
 
 #***************************************************************************
 # Validate username
@@ -1193,7 +1193,7 @@ if($rc == -1) {
 }
 elsif($rc & 127) {
     logmsg sprintf("\"$sshd\" died with signal %d, and %s coredump\n",
-                   ($rc & 127), ($rc & 128)?'a':'no');
+                   ($rc & 127), ($rc & 128) ? 'a' : 'no');
 }
 elsif($verbose && ($rc >> 8)) {
     logmsg sprintf("\"$sshd\" exited with %d\n", $rc >> 8);