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

lib/imap.c

@@ -1141,7 +1141,7 @@ static CURLcode imap_state_auth_resp(struct Curl_easy *data,
       imap_state(data, imapc, IMAP_STOP);  /* Authenticated */
       break;
     case SASL_IDLE:            /* No mechanism left after cancellation */
-      if((!imapc->login_disabled) && (imapc->preftype & IMAP_TYPE_CLEARTEXT))
+      if(!imapc->login_disabled && (imapc->preftype & IMAP_TYPE_CLEARTEXT))
         /* Perform clear text authentication */
         result = imap_perform_login(data, imapc, data->conn);
       else {