Make all libcurl related options use .nf (no fill) for the SYNOPSIS
section - for consistent look. roffit then renders that section using
<pre> (monospace font) in html for the website.
Extended manpage-syntax (test 1173) with a basic check for it.
Closes#8062
Since HTTPS is "the new normal", this update changes a lot of man page
examples to use https://example.com instead of the previous "http://..."
Closes#5969
Use an ephemeral port number here; previously the example had 8080
which could be confusing as the common web server port number might
be misinterpreted as suggesting this option affects the remote port.
URL: https://curl.haxx.se/mail/lib-2019-01/0084.htmlCloses#3513
