In documentation, suggest using Postgres type inet for storing IPs

It is the core Postgres type to store IP addresses.

user_guide_src/source/libraries/sessions.rst

@@ -594,7 +594,7 @@ For PostgreSQL::
 
 	CREATE TABLE "ci_sessions" (
 		"id" varchar(128) NOT NULL,
-		"ip_address" varchar(45) NOT NULL,
+		"ip_address" inet NOT NULL,
 		"timestamp" timestamptz DEFAULT CURRENT_TIMESTAMP NOT NULL,
 		"data" bytea DEFAULT '' NOT NULL
 	);