docs: Update pinout documentation with enhanced pin mapping

Pinout Documentation Updates (03_pinout.rst):
- Enhanced pin mapping descriptions and clarity
- Improved GPIO pin assignments documentation
- Updated visual references and layout
- Better organization of pin function descriptions
- Enhanced readability and technical accuracy

These updates provide clearer guidance for pin usage on the PULSAR H2 board and improve the overall developer experience for hardware interfacing.

Author: GitHub Actions

software/sphinx/src/source/03_pinout.rst

@@ -23,9 +23,9 @@ Pinout distribution
       <br><br>
 
       <!-- Imagen que se puede abrir en una nueva ventana al hacer clic -->
-      <a href="./_static/nanoh2/pinout.png" target="_blank">
+      <a href="./_static/nanoh2/pinout.jpg" target="_blank">
         <img
-           src="./_static/nanoh2/pinout.png"
+           src="./_static/nanoh2/pinout.jpg"
            alt="PULSAR H2 Pinout"
            style="width: 90%; height: auto; border: 1px solid #ccc; border-radius: 8px;"
         >