fix typo in error

Author: ccasin

ocaml/testsuite/tests/typing-layouts-float64/basics_alpha_beta.ml

@@ -322,7 +322,7 @@ type f7_4 = [ `A of t_float64 ];;
 Line 1, characters 20-29:
 1 | type f7_4 = [ `A of t_float64 ];;
                         ^^^^^^^^^
-Error: Polymorpic variant constructor argument types must have layout value.
+Error: Polymorphic variant constructor argument types must have layout value.
         t_float64 has layout float64, which is not a sublayout of value.
 |}];;
 

ocaml/testsuite/tests/typing-layouts/basics_alpha.ml

@@ -447,7 +447,7 @@ end
 Line 2, characters 40-46:
 2 |   type foo1 = [ `Foo1 of int | `Baz1 of t_void | `Bar1 of string ];;
                                             ^^^^^^
-Error: Polymorpic variant constructor argument types must have layout value.
+Error: Polymorphic variant constructor argument types must have layout value.
         t_void has layout void, which is not a sublayout of value.
 |}];;
 
@@ -501,7 +501,7 @@ end;;
 Line 2, characters 17-23:
 2 |   val x : [`A of t_void]
                      ^^^^^^
-Error: Polymorpic variant constructor argument types must have layout value.
+Error: Polymorphic variant constructor argument types must have layout value.
         t_void has layout void, which is not a sublayout of value.
 |}]
 

ocaml/testsuite/tests/typing-layouts/basics_beta.ml

@@ -316,7 +316,7 @@ end
 Line 2, characters 40-49:
 2 |   type foo1 = [ `Foo1 of int | `Baz1 of t_float64 | `Bar1 of string ];;
                                             ^^^^^^^^^
-Error: Polymorpic variant constructor argument types must have layout value.
+Error: Polymorphic variant constructor argument types must have layout value.
         t_float64 has layout float64, which is not a sublayout of value.
 |}];;
 
@@ -368,7 +368,7 @@ end;;
 Line 2, characters 17-26:
 2 |   val x : [`A of t_float64]
                      ^^^^^^^^^
-Error: Polymorpic variant constructor argument types must have layout value.
+Error: Polymorphic variant constructor argument types must have layout value.
         t_float64 has layout float64, which is not a sublayout of value.
 |}]
 

ocaml/typing/typetexp.ml

@@ -1369,7 +1369,7 @@ let report_error env ppf = function
     let s =
       match vloc with
       | Tuple -> "Tuple element"
-      | Poly_variant -> "Polymorpic variant constructor argument"
+      | Poly_variant -> "Polymorphic variant constructor argument"
       | Package_constraint -> "Signature package constraint"
       | Object_field -> "Object field"
     in