- lib650: pass `long` to `CURLFORM_NAMELENGTH` in test.
Spotted by Copilot.
https://github.com/curl/curl/pull/22011#discussion_r3412407235
Follow-up to 3620e569b3
- lib650: drop an interim variable, and interim casts.
Follow-up to 60776a0515#2747
- curl_formdata.md: document `CURLFORM_NAMELENGTH` on man page.
- curl_formdata.md: pass `long` to `CURLFORM_BUFFERLENGTH` on man page.
- formdata: pass `long` to `CURLFORM_CONTENTSLENGTH` in comment.
Closes#22017