- Add protocols field to max-filesize.d.
- Revert wording on unknown file size caveat and do not discuss specific
protocols in that section.
Partial revert of ecf0225. All max-filesize options now have the list of
protocols and it's clearer just to have that list without discussing
specific protocols in the caveat.
Reported-by: Josh Soref
Ref: https://github.com/curl/curl/issues/7453#issuecomment-884128762
Also make it clearer that the caveat 'if the file size is unknown it
the option will have no effect' may apply to protocols other than FTP
and HTTP.
Reported-by: Josh Soref
Fixes https://github.com/curl/curl/issues/7453
