rename "sega 2P plus one" layouts + etc. as "sega 2P nine"

seems more coherent, and fits with the newer sega 2P eleven layout I
made, even if I'm going to end up sticking with nine in my builds

Signed-off-by: Brian S. Stephan <bss@incorporeal.org>

src/panels/overhang/right-sega-2p-nine-panel.scad

@@ -0,0 +1,17 @@
+/*
+ * SPDX-FileCopyrightText: © 2023 Brian S. Stephan <bss@incorporeal.org>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+include <parameters.scad>
+include <components.scad>
+
+module sega_2p_nine_right_overhang_panel() {
+	difference() {
+		panel_with_raised_overhang();
+		sega_2p_nine();
+		rotate([0, 0, 180]) side_chopper();
+	}
+}
+
+sega_2p_nine_right_overhang_panel();