Fix typo

Change-Id: I23e3617274c1c17b9c3792f95eaf28d9554dc2b3
Reviewed-on: https://gerrit.libreoffice.org/70740
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>
Tested-by: Julien Nabet <serval2412@yahoo.fr>

cli_ure/source/basetypes/uno/PolymorphicType.cs

@@ -108,7 +108,7 @@ public class PolymorphicType: Type
         if (name == null || type == null)
             throw new ArgumentNullException(
                 "cli-uno: uno.PolymorphicType.GetType was called with a null argument");
-        //check if the type is either a array of structs or a polymorphic struct.
+        //check if the type is either an array of structs or a polymorphic struct.
         if (type.IsArray)
         {
             Type elementType = type;