NRT tweak on GetConstructorParameter

Author: mgravell

Dapper/PublicAPI.Shipped.txt

@@ -135,7 +135,7 @@ Dapper.SqlMapper.ITypeHandler.SetValue(System.Data.IDbDataParameter! parameter,
 Dapper.SqlMapper.ITypeMap
 Dapper.SqlMapper.ITypeMap.FindConstructor(string![]! names, System.Type![]! types) -> System.Reflection.ConstructorInfo?
 Dapper.SqlMapper.ITypeMap.FindExplicitConstructor() -> System.Reflection.ConstructorInfo?
-Dapper.SqlMapper.ITypeMap.GetConstructorParameter(System.Reflection.ConstructorInfo! constructor, string! columnName) -> Dapper.SqlMapper.IMemberMap!
+Dapper.SqlMapper.ITypeMap.GetConstructorParameter(System.Reflection.ConstructorInfo! constructor, string! columnName) -> Dapper.SqlMapper.IMemberMap?
 Dapper.SqlMapper.ITypeMap.GetMember(string! columnName) -> Dapper.SqlMapper.IMemberMap?
 Dapper.SqlMapper.Settings
 Dapper.SqlMapper.StringTypeHandler<T>

Dapper/SqlMapper.ITypeMap.cs

@@ -33,7 +33,7 @@ public interface ITypeMap
             /// <param name="constructor">Constructor to resolve</param>
             /// <param name="columnName">DataReader column name</param>
             /// <returns>Mapping implementation</returns>
-            IMemberMap GetConstructorParameter(ConstructorInfo constructor, string columnName);
+            IMemberMap? GetConstructorParameter(ConstructorInfo constructor, string columnName);
 
             /// <summary>
             /// Gets member mapping for column