Fix join for tuple

Author: gusty

src/FSharpPlus/Control/Monad.fs

@@ -93,7 +93,7 @@ type Join =
     static member        Join (x: list<list<_>>         , [<Optional>]_output: list<'T>        , [<Optional>]_mthd: Join    ) = List.concat x              : list<'T>
     static member        Join (x: _ [][]                , [<Optional>]_output: 'T []           , [<Optional>]_mthd: Join    ) = Array.concat x             : 'T []
     static member        Join (g                        , [<Optional>]_output: 'R->'T          , [<Optional>]_mthd: Join    ) = (fun r -> (g r) r)         : 'R->'T
-    static member inline Join (m1, (m2, x)              , [<Optional>]_output: 'Monoid * 'T    , [<Optional>]_mthd: Join    ) = Plus.Invoke m1 m2, x       : 'Monoid*'T
+    static member inline Join ((m1, (m2, x))              , [<Optional>]_output: 'Monoid * 'T    , [<Optional>]_mthd: Join    ) = Plus.Invoke m1 m2, x       : 'Monoid*'T
     static member inline Join (struct (m1, struct (m2, x)), [<Optional>]_output: struct ('Monoid * 'T), [<Optional>]_mthd: Join) = Plus.Invoke m1 m2, x    : struct ('Monoid * 'T)
     static member        Join (x                        , [<Optional>]_output: Async<'T>       , [<Optional>]_mthd: Join    ) = async.Bind (x, id)         : Async<'T>
     static member        Join (x                        , [<Optional>]_output: Result<'T,'E>   , [<Optional>]_mthd: Join    ) = Result.flatten x           : Result<'T,'E>