Add error code 2601 (#153)

SQL Server have two slightly different error codes for duplicate key errors:
2627 occurs on unique/PK constraint violations, while 2601 is triggered by unique index violations.
Both indicate duplicate keys but stem from different schema definitions.

Co-authored-by: Rasmus Nordström <[email protected]>

Author: RasmusN

error_translator.go

@@ -9,6 +9,7 @@ import (
 // The error codes to map mssql errors to gorm errors, here is a reference about error codes for mssql https://learn.microsoft.com/en-us/sql/relational-databases/errors-events/database-engine-events-and-errors?view=sql-server-ver16
 var errCodes = map[int32]error{
 	2627: gorm.ErrDuplicatedKey,
+	2601: gorm.ErrDuplicatedKey,
 	547:  gorm.ErrForeignKeyViolated,
 }
 

error_translator_test.go

@@ -27,6 +27,11 @@ func TestDialector_Translate(t *testing.T) {
 			args: args{err: mssql.Error{Number: 2627}},
 			want: gorm.ErrDuplicatedKey,
 		},
+		{
+			name: "it should return ErrDuplicatedKey error if the error number is 2601",
+			args: args{err: mssql.Error{Number: 2601}},
+			want: gorm.ErrDuplicatedKey,
+		},
 		{
 			name: "it should return ErrForeignKeyViolated the error number is 547",
 			args: args{err: mssql.Error{Number: 547}},