Add UserToken debug info

Author: VladislavFitz

Sources/AlgoliaSearchClient/Models/Common/UserToken.swift

@@ -15,9 +15,9 @@ public struct UserToken: StringWrapper, URLEncodable {
 
   public init(rawValue: String) {
     assert(!rawValue.isEmpty, "UserToken can't be empty")
-    assert(rawValue.count <= 64, "UserToken length can't be superior to 64 characters.")
+    assert(rawValue.count <= 64, "UserToken length can't be superior to 64 characters. Input: \(rawValue)")
     let containsOnlyAllowedCharacters = rawValue.trimmingCharacters(in: allowedCharacters).isEmpty
-    assert(containsOnlyAllowedCharacters, "UserToken allows only characters of type [a-zA-Z0-9_-]")
+    assert(containsOnlyAllowedCharacters, "UserToken allows only characters of type [a-zA-Z0-9_-]. Input: \(rawValue)")
     self.rawValue = rawValue
   }