input: add direct set_surface_title and set_tab_title actions

Fixes #11316

This mirrors the `prompt` actions (hence why there is no window action
here) and enables setting titles via keybind actions which importantly
lets this work via command palettes, App Intents, AppleScript, etc.

src/apprt/action.zig

@@ -201,6 +201,9 @@ pub const Action = union(Key) {
     /// Set the title of the target to the requested value.
     set_title: SetTitle,
 
+    /// Set the tab title override for the target's tab.
+    set_tab_title: SetTitle,
+
     /// Set the title of the target to a prompted value. It is up to
     /// the apprt to prompt. The value specifies whether to prompt for the
     /// surface title or the tab title.
@@ -375,6 +378,7 @@ pub const Action = union(Key) {
         render_inspector,
         desktop_notification,
         set_title,
+        set_tab_title,
         prompt_title,
         pwd,
         mouse_shape,