feat: implement a working WinScrolled autocmd

src/nvim/window.c

@@ -4965,6 +4965,30 @@ void shell_new_columns(void)
   win_reconfig_floats();  // The size of floats might change
 }
 
+/*
+ * Check if "wp" has scrolled since last time it was checked
+ */
+bool win_did_scroll(win_T *wp)
+{
+  return (curwin->w_last_topline != curwin->w_topline ||
+          curwin->w_last_leftcol != curwin->w_leftcol ||
+          curwin->w_last_width != curwin->w_width ||
+          curwin->w_last_height != curwin->w_height);
+}
+
+/*
+ * Trigger WinScrolled autocmd
+ */
+void do_autocmd_winscrolled(win_T *wp)
+{
+  apply_autocmds(EVENT_WINSCROLLED, NULL, NULL, false, curbuf);
+
+  wp->w_last_topline = wp->w_topline;
+  wp->w_last_leftcol = wp->w_leftcol;
+  wp->w_last_width = wp->w_width;
+  wp->w_last_height = wp->w_height;
+}
+
 /*
  * Save the size of all windows in "gap".
  */