Add newlines at end of files

Author: MaxDesiatov

Sources/JavaScriptKit/BasicObjects/JSError.swift

@@ -17,4 +17,4 @@ public final class JSError {
 
 extension JSError: CustomStringConvertible {
     public var description: String { ref.description }
-}
+}

Sources/JavaScriptKit/FundamentalObjects/JSObject.swift

@@ -50,4 +50,4 @@ public class JSObject: Equatable {
 
 extension JSObject: CustomStringConvertible {
     public var description: String { self.toString!().string! }
-}
+}