Send alt key with actual key in one flush

The delay between the alt key and the actual received key might cause
certain key sequences to be missed, ex. when tmux has its escape-time
set to 0.

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix color issue in ncurses programs by updating terminfo pairs from 0x10000 to 0x7FFF
 - Fix panic after quitting Alacritty on macOS
 - Tabs are no longer replaced by spaces when copying them to the clipboard
+- Alt modifier is no longer sent separately from the modified key
 
 ## Version 0.2.4
 

src/input.rs

@@ -687,16 +687,16 @@ impl<'a, A: ActionContext + 'a> Processor<'a, A> {
             self.ctx.clear_selection();
 
             let utf8_len = c.len_utf8();
-            if *self.ctx.received_count() == 0 && self.ctx.last_modifiers().alt && utf8_len == 1 {
-                self.ctx.write_to_pty(b"\x1b".to_vec());
-            }
-
             let mut bytes = Vec::with_capacity(utf8_len);
             unsafe {
                 bytes.set_len(utf8_len);
                 c.encode_utf8(&mut bytes[..]);
             }
 
+            if *self.ctx.received_count() == 0 && self.ctx.last_modifiers().alt && utf8_len == 1 {
+                bytes.insert(0, b'\x1b');
+            }
+
             self.ctx.write_to_pty(bytes);
 
             *self.ctx.received_count() += 1;