fix warnings

DcCore/DcCore/DC/Wrapper.swift

@@ -160,6 +160,7 @@ public class DcContext {
         return DcMsg(pointer: messagePointer)
     }
 
+    @discardableResult
     public func sendMessage(chatId: Int, message: DcMsg) -> Int {
         return Int(dc_send_msg(contextPointer, UInt32(chatId), message.messagePointer))
     }
@@ -639,7 +640,7 @@ public class DcContext {
 
                     let isIndependet = dc_array_is_independent(array, i) != 0
                     var label: String = ""
-                    var name: String = names[contactId] ?? "ErrName"
+                    let name: String = names[contactId] ?? "ErrName"
                     if isIndependet {
                         if let cString = dc_array_get_marker(array, i) {
                             label = String(cString: cString) // get_marker() returns one-char labels only