docs(ipam): document expected format of requested IP (scaleway#2069)

Author: scaleway-bot

api/ipam/v1/ipam_sdk.go

@@ -209,7 +209,7 @@ type BookIPRequest struct {
 // IsIPv6: request an IPv6 instead of an IPv4.
 IsIPv6 bool `json:"is_ipv6"`
 
-// Address: note that only the Private Network source allows you to pick a specific IP. If the requested IP is already booked, then the call will fail.
+// Address: the requested address should not include the subnet mask (/suffix). Note that only the Private Network source allows you to pick a specific IP. If the requested IP is already booked, then the call will fail.
 Address *net.IP `json:"address,omitempty"`
 
 // Tags: tags for the IP.