tidy-up: miscellaneous

- INSTALL-CMAKE.md: add missing periods, text fixes.
- md4, md5: sync variables names.
- curl_trc: sync an argument type.
- docs/examples: sync debug/trace function copies, constify, tidy-ups.
- replace commented code with `#if 0`.
- drop redundant parenthesis (macro values, `return`, around single
  variables, function calls).
- fix indentation, apply clang-format in places.

Closes #20481

lib/easy.c

@@ -616,7 +616,9 @@ static CURLcode wait_or_timeout(struct Curl_multi *multi, struct events *ev)
     if(!pollrc) {
       /* timeout! */
       ev->ms = 0;
-      /* curl_mfprintf(stderr, "call curl_multi_socket_action(TIMEOUT)\n"); */
+#if 0
+      curl_mfprintf(stderr, "call curl_multi_socket_action(TIMEOUT)\n");
+#endif
       mresult = curl_multi_socket_action(multi, CURL_SOCKET_TIMEOUT, 0,
                                          &ev->running_handles);
     }