docs(zlant_xl): add readme.md, updated keymap.c with correct year

keyboards/zlant_xl/keymaps/default/keymap.c

@@ -1,4 +1,4 @@
-/* Copyright 2021 Christian C. Berclaz
+/* Copyright 2024 Christian C. Berclaz
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by

keyboards/zlant_xl/readme.md

@@ -0,0 +1,26 @@
+# ZLANT XL
+
+![ZLANT XL](<https://1upkeyboards.com/wp-content/uploads/2021/06/ZlantXL-scaled.jpeg>
+_A unique 50% mechanical keyboard that uses a slanted ortholinear layout_
+
+- Keyboard Maintainer: [chrisgve](https://github.com/chrisgve)
+- Hardware Supported: Zlant XL w/Ziptyze's atmega32u2 powered controller [The Rune](https://1upkeyboards.com/shop/controllers/the-rune-by-ziptyze/)
+- Hardware Availability: [1UP Keyboards](https://1upkeyboards.com/shop/keyboard-kits/diy-40-kits/zlantxl-50-mechanical-keyboard-kit/)
+
+Make example for this keyboard (after setting up your build environment):
+
+    make zlant_xl:default
+
+Flashing example for this keyboard:
+
+    make zlant_xl:default:flash
+
+See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).
+
+## Bootloader
+
+Enter the bootloader in 3 ways:
+
+- **Bootmagic reset**: Hold down the key at (0,0) in the matrix (usually the top left key or Escape) and plug in the keyboard
+- **Physical reset button**: Briefly press the button on the back of the PCB - some may have pads you must short instead
+- **Keycode in layout**: Press the key mapped to `QK_BOOT` if it is available