CURLOPT: drop redundant long casts

Also:
- CURLOPT_HSTS_CTRL.md: sync macro definitions with `curl/curl.h`.
  Perhaps it'd be better to delete copies like this?
- keep existing casts within the documentation to make sure it applies
  to older curl versions as well.
- CURLOPT_IPRESOLVE.md: re-add a long cast to man page, for consistency
  with the above.

Closes #17791

docs/examples/anyauthput.c

@@ -142,7 +142,7 @@ int main(int argc, char **argv)
     /* tell libcurl we can use "any" auth, which lets the lib pick one, but it
        also costs one extra round-trip and possibly sending of all the PUT
        data twice!!! */
-    curl_easy_setopt(curl, CURLOPT_HTTPAUTH, (long)CURLAUTH_ANY);
+    curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
 
     /* set user name and password for the authentication */
     curl_easy_setopt(curl, CURLOPT_USERPWD, "user:password");