win32: fix encoding of delete and backspace keys

When using the win32 keyboard encoding, the delete and backspace keys
were encoded with the wrong character codes compared to the native
terminal. This caused subtle issues in multiple applications.

This change brings the encoding in line with the native terminal.

wezterm-input-types/src/lib.rs

@@ -1222,13 +1222,33 @@ impl KeyEvent {
         match &self.key {
             KeyCode::Composed(_) => None,
             KeyCode::Char(c) => {
+                let c = match *c {
+                    // Delete key is transmitted as 0x0
+                    '\x7f' => '\x00',
+                    // Backspace key is transmitted as 0x8, 0x7f or 0x0
+                    '\x08' => {
+                        if self.modifiers.contains(Modifiers::CTRL) {
+                            if self.modifiers.contains(Modifiers::ALT)
+                                || self.modifiers.contains(Modifiers::SHIFT)
+                            {
+                                '\x00'
+                            } else {
+                                '\x7f'
+                            }
+                        } else {
+                            '\x08'
+                        }
+                    }
+                    _ => *c,
+                };
+
                 let c = if self.modifiers.contains(Modifiers::CTRL) {
                     // Ensure that we rewrite the unicode value to the ASCII CTRL
                     // equivalent value.
                     // <https://github.com/microsoft/terminal/issues/13134>
-                    ctrl_mapping(*c).unwrap_or(*c)
+                    ctrl_mapping(c).unwrap_or(c)
                 } else {
-                    *c
+                    c
                 };
                 let uni = c as u32;