tidy-up: miscellaneous

- badwords: replace stray synonyms with 'null-terminator'.
- tests/FILEFORMAT.md: tidy up feature descriptions.
- printf: replace stray `%i` masks with `%d` for consistency.
- pytest: add comments for empty excepts to try silencing GitHub CodeQL
  warnings.
- tool1394, unit1675: merge nested `if`s.
- dnscache: fix typo in comment.
- fix whitespace, indent and newlines.

Closes #21921

lib/cf-haproxy.c

@@ -91,7 +91,7 @@ static CURLcode cf_haproxy_date_out_set(struct Curl_cfilter *cf,
     client_dest_ip = ipquad.remote_ip;
   }
 
-  result = curlx_dyn_addf(&ctx->data_out, "PROXY %s %s %s %i %i\r\n",
+  result = curlx_dyn_addf(&ctx->data_out, "PROXY %s %s %s %d %d\r\n",
                           is_ipv6 ? "TCP6" : "TCP4",
                           client_source_ip, client_dest_ip,
                           ipquad.local_port, ipquad.remote_port);