Correct casing of Stdlib::IP::Address

While Puppet doesn't appear to care about IP vs Ip, but Kafo does and
can't find the correct type. This aligns the usage with the actual name
in the file.

Fixes: fcbd426 ("Remove deprecated Stdlib::Compat::* data types")

Author: ekohl

REFERENCE.md

@@ -5619,7 +5619,7 @@ Alias of `Pattern[/(?i:\Ahttps?:\/\/.*\z)/]`
 
 Validate a host (FQDN or IP address)
 
-Alias of `Variant[Stdlib::Fqdn, Stdlib::Ip::Address]`
+Alias of `Variant[Stdlib::Fqdn, Stdlib::IP::Address]`
 
 ### <a name="Stdlib--Http--Method"></a>`Stdlib::Http::Method`
 

types/host.pp

@@ -1,2 +1,2 @@
 # @summary Validate a host (FQDN or IP address)
-type Stdlib::Host = Variant[Stdlib::Fqdn, Stdlib::Ip::Address]
+type Stdlib::Host = Variant[Stdlib::Fqdn, Stdlib::IP::Address]