fix: memory corruption in Screen.cursorAbsolute

We call `cursorChangePin` which may invalidate the provided pin if it
needs to adjust the page capacity, and as such we should consider the
pin we pass in to it invalid afterwards, and access it through cursor
instead.

src/terminal/Screen.zig

@@ -620,7 +620,7 @@ pub fn cursorAbsolute(self: *Screen, x: size.CellCountInt, y: size.CellCountInt)
     self.cursor.x = x; // Must be set before cursorChangePin
     self.cursor.y = y;
     self.cursorChangePin(page_pin);
-    const page_rac = page_pin.rowAndCell();
+    const page_rac = self.cursor.page_pin.rowAndCell();
     self.cursor.page_row = page_rac.row;
     self.cursor.page_cell = page_rac.cell;
 }