doc/kdig: improve the description of the URL parameter

doc/man/kdig.1in

@@ -280,7 +280,10 @@ considered invalid.
 \fB+\fP[\fBno\fP]\fBhttps\fP[=\fIURL\fP]
 Use HTTPS (DNS\-over\-HTTPS) in wire format (\fI\%RFC 1035#section\-4.2.1\fP).
 It is also possible to specify URL=[authority][/path] where request
-will be send. Authority might also be specified as server name (parameter \fI@\fP).
+will be sent to. Any leading scheme and authority indicator (i.e. //) are ignored.
+Authority might also be specified as the \fIserver\fP (using the parameter \fI@\fP).
+If \fIpath\fP is specified and \fIauthority\fP is missing, then the \fIserver\fP
+is used as authority together with the specified \fIpath\fP\&.
 Library \fIlibnghttp2\fP is required.
 .TP
 \fB+\fP[\fBno\fP]\fBhttps\-get\fP

doc/man_kdig.rst

@@ -259,7 +259,10 @@ Options
 **+**\ [\ **no**\ ]\ **https**\[\ =\ *URL*\]
   Use HTTPS (DNS-over-HTTPS) in wire format (:rfc:`1035#section-4.2.1`).
   It is also possible to specify URL=\[authority\]\[/path\] where request
-  will be send. Authority might also be specified as server name (parameter `@`).
+  will be sent to. Any leading scheme and authority indicator (i.e. //) are ignored.
+  Authority might also be specified as the *server* (using the parameter `@`).
+  If *path* is specified and *authority* is missing, then the *server*
+  is used as authority together with the specified *path*.
   Library *libnghttp2* is required.
 
 **+**\ [\ **no**\ ]\ **https-get**