Do not render ligatures under cursor

kitty/state.h

@@ -35,6 +35,7 @@ typedef struct {
     float window_padding_width;
     Edge tab_bar_edge;
     unsigned long tab_bar_min_tabs;
+    bool disable_ligatures_under_cursor;
     bool sync_to_monitor;
     bool close_on_child_death;
     bool window_alert_on_bell;