Give an error that makes sense for the user

Also, that coincides with docs

Author: ahstro

Diff for: src/Validate/SSN/Swedish.elm

@@ -82,6 +82,7 @@ validateAndNormalize : Maybe Date -> String -> Result String String
 validateAndNormalize date ssn =
     ssn
         |> Helpers.matchOne ssnRegex
+        |> Result.mapError (\_ -> "Invalid Swedish SSN")
         |> Result.map .submatches
         |> Result.andThen (assembleNormalized date)
         |> Result.andThen luhnValidate