Add note to IorNel

docs/src/main/tut/datatypes/ior.md

@@ -60,7 +60,7 @@ case class User(name: Username, pw: Password)
 
 def validateUsername(u: String): Failures Ior Username = {
   if (u.isEmpty)
-    Ior.leftNel("Can't be empty")
+    Nel("Can't be empty").leftIor
   else if (u.contains("."))
     Ior.both(Nel.one("Dot in name is deprecated"), Username(u))
   else
@@ -69,7 +69,7 @@ def validateUsername(u: String): Failures Ior Username = {
 
 def validatePassword(p: String): Failures Ior Password = {
   if (p.length < 8)
-    Ior.leftNel("Password too short")
+    Nel("Password too short").leftIor
   else if (p.length < 10)
     Ior.both(Nel.one("Password should be longer"), Password(p))
   else
@@ -103,6 +103,18 @@ validateUser("john.doe", "password").fold(
   (warnings, user) => s"Warning: ${user.name.value}; The following warnings occurred: ${warnings.show}"
 )
 
+```
+Similar to [Validated](validated.html), there is also a type alias for using a `NonEmptyList` on the left side.
+
+```tut:silent
+type IorNel[B, A] = Ior[NonEmptyList[B], A]
+```
+
+
+```tut
+
+val left: IorNel[String, Int] = Ior.leftNel("Error")
+
 ```