Emulate Unix like terminals that sends Alt+key as \e+key

Author: aycabta

lib/reline/windows.rb

@@ -226,6 +226,8 @@ def self.process_key_event(repeat_count, virtual_key_code, virtual_scan_code, ch
     # no char, only control keys
     return if key.char_code == 0 and key.control_keys.any?
 
+    @@output_buf.push("\e".ord) if key.control_keys.include?(:ALT)
+
     @@output_buf.concat(key.char.bytes)
   end