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/request.c

@@ -292,7 +292,7 @@ static CURLcode req_flush(struct Curl_easy *data)
       return result;
     if(!Curl_bufq_is_empty(&data->req.sendbuf)) {
       DEBUGF(infof(data, "Curl_req_flush(len=%zu) -> EAGAIN",
-             Curl_bufq_len(&data->req.sendbuf)));
+                   Curl_bufq_len(&data->req.sendbuf)));
       return CURLE_AGAIN;
     }
   }