Deprecate <**>

Author: gusty

src/FSharpPlus/Operators.fs

@@ -206,9 +206,7 @@ module Operators =
     /// <category index="2">Applicative</category>
     let inline (<*  ) (x: '``Applicative<'U>``) (y: '``Applicative<'T>``) : '``Applicative<'U>`` = ((fun (k: 'U) (_: 'T) -> k ) <!> x : '``Applicative<'T->'U>``) <*> y
 
-    /// <summary>
-    /// Apply a lifted argument to a lifted function (flipped): arg &lt;**&gt; f
-    /// </summary>
+    [<System.Obsolete("Use flip (<*>) instead.")>]
     /// <category index="2">Applicative</category>
     let inline (<**>) (x: '``Applicative<'T>``) : '``Applicative<'T -> 'U>``->'``Applicative<'U>`` = flip (<*>) x