Make AlphaVantageError conform to LocalizedError

Author: adborbas

Sources/AlphaSwiftage/Public/AlphaVantageError.swift

@@ -7,10 +7,21 @@
 
 import Foundation
 
-public enum AlphaVantageError: Error {
+public enum AlphaVantageError: Error, LocalizedError {
     case apiError(AlphaVantageAPIError)
     case unexpectedResponse(String)
     case unknown(Error)
+    
+    public var errorDescription: String? {
+        switch self {
+        case .apiError(let apiError):
+            return apiError.errorDescription
+        case .unexpectedResponse(let response):
+            return response
+        case .unknown(let error):
+            return error.localizedDescription
+        }
+    }
 }
 
 public struct AlphaVantageAPIError: Codable, LocalizedError, Equatable {