hostip: make CURLOPT_RESOLVE support replacing IPv6 addresses

This also applies to --resolve of course.

Applied strparse functions on the function.

Fixes #16357
Reported-by: rmg-x on github
Closes #16358
Assisted-by: Jay Satiro

docs/cmdline-opts/resolve.md

@@ -12,6 +12,7 @@ See-also:
   - alt-svc
 Example:
   - --resolve example.com:443:127.0.0.1 $URL
+  - --resolve example.com:443:[2001:db8::252f:efd6] $URL
 ---
 
 # `--resolve`
@@ -20,8 +21,8 @@ Provide a custom address for a specific host and port pair. Using this, you
 can make the curl requests(s) use a specified address and prevent the
 otherwise normally resolved address to be used. Consider it a sort of
 /etc/hosts alternative provided on the command line. The port number should be
-the number used for the specific protocol the host is used for. It means
-you need several entries if you want to provide address for the same host but
+the number used for the specific protocol the host is used for. It means you
+need several entries if you want to provide addresses for the same host but
 different ports.
 
 By specifying `*` as host you can tell curl to resolve any host and specific
@@ -37,9 +38,13 @@ parallel transfers with a lot of files. In such cases, if this option is used
 curl tries to resolve the host as it normally would once the timeout has
 expired.
 
+Provide IPv6 addresses within [brackets].
+
 To redirect connects from a specific hostname or any hostname, independently
 of port number, consider the --connect-to option.
 
 Support for resolving with wildcard was added in 7.64.0.
 
 Support for the '+' prefix was added in 7.75.0.
+
+Support for specifying the host component as an IPv6 address was added in 8.13.0.