Add serde-alias for on_force_close

* It doesn't deserialize from the configuration otherwise,
  if specified in lower-case.

Alternative: use a rename.

zellij-utils/src/input/options.rs

@@ -8,7 +8,9 @@ use zellij_tile::data::InputMode;
 
 #[derive(Copy, Clone, Debug, PartialEq, Deserialize, Serialize)]
 pub enum OnForceClose {
+    #[serde(alias = "quit")]
     Quit,
+    #[serde(alias = "detach")]
     Detach,
 }