docs/: Add installation reference.

Signed-off-by: wxyyy0117 <[email protected]>

Author: wxyyy0117

docs/development-instructions.rst

@@ -20,6 +20,7 @@ Environment Setup
    * Install `Arduino IDE (2.0 or higher) <https://docs.arduino.cc/software/ide-v2/tutorials/getting-started/ide-v2-downloading-and-installing/>`_ 
    * Or Install `Arduino CLI (1.0.0 or higher) <https://arduino.github.io/arduino-cli/latest/installation/>`_
    * Python
+   * Follow the :doc:`installation-instructions`
 
 #. Create a ``<SKETCHBOOK>/hardware/arduino-git`` folder. Where ``<SKETCHBOOK>`` is the location of your Arduino sketchbook. The ``<SKETCHBOOK>`` default is OS-dependent: