Use second level headers on notes page

docs/notes.md

@@ -1,78 +1,84 @@
 # Notes
 
-1. **BCM pin numbering**
+## BCM pin numbering
 
-    This library uses Broadcom (BCM) pin numbering for the GPIO pins, as
-    opposed to BOARD. Unlike the `RPi.GPIO` library, this is not configurable.
+This library uses Broadcom (BCM) pin numbering for the GPIO pins, as
+opposed to BOARD. Unlike the `RPi.GPIO` library, this is not configurable.
 
-    Any pin marked `GPIO` can be used for generic components.
+Any pin marked `GPIO` can be used for generic components.
 
-    The BCM pin layout is as follows:
+The BCM pin layout is as follows:
 
-    |            |            |
-    |-----------:|:-----------|
-    |    3V3     | 5V         |
-    |  **GPIO2** | 5V         |
-    |  **GPIO3** | GND        |
-    |  **GPIO4** | **GPIO14** |
-    |        GND | **GPIO15** |
-    | **GPIO17** | **GPIO18** |
-    | **GPIO27** | GND        |
-    | **GPIO22** | **GPIO23** |
-    |        3V3 | **GPIO24** |
-    | **GPIO10** | GND        |
-    |  **GPIO9** | **GPIO25** |
-    | **GPIO11** | **GPIO8**  |
-    |        GND | **GPIO7**  |
-    |        DNC | DNC        |
-    |  **GPIO5** | GND        |
-    |  **GPIO6** | **GPIO12** |
-    | **GPIO13** | GND        |
-    | **GPIO19** | **GPIO16** |
-    | **GPIO26** | **GPIO20** |
-    |        GND | **GPIO21** |
+|            |            |
+|-----------:|:-----------|
+|    3V3     | 5V         |
+|  **GPIO2** | 5V         |
+|  **GPIO3** | GND        |
+|  **GPIO4** | **GPIO14** |
+|        GND | **GPIO15** |
+| **GPIO17** | **GPIO18** |
+| **GPIO27** | GND        |
+| **GPIO22** | **GPIO23** |
+|        3V3 | **GPIO24** |
+| **GPIO10** | GND        |
+|  **GPIO9** | **GPIO25** |
+| **GPIO11** | **GPIO8**  |
+|        GND | **GPIO7**  |
+|        DNC | DNC        |
+|  **GPIO5** | GND        |
+|  **GPIO6** | **GPIO12** |
+| **GPIO13** | GND        |
+| **GPIO19** | **GPIO16** |
+| **GPIO26** | **GPIO20** |
+|        GND | **GPIO21** |
 
-    - *GND = Ground*
-    - *3V3 = 3.3 Volts*
-    - *5V = 5 Volts*
-    - *DNC = Do not connect (special use pins)*
+- *GND = Ground*
+- *3V3 = 3.3 Volts*
+- *5V = 5 Volts*
+- *DNC = Do not connect (special use pins)*
 
-2.  **Wiring**
+## Wiring
 
-    All components must be wired up correctly before using with this library.
+All components must be wired up correctly before using with this library.
 
-3.  **Keep your program alive with `signal.pause`**
+## Keep your program alive with `signal.pause`
 
-    The following program looks like it should turn an LED on:
+The following program looks like it should turn an LED on:
 
-        from gpiozero import led
+```python
+from gpiozero import led
 
-        led = LED(2)
-        led.on()
+led = LED(2)
+led.on()
+```
 
-    And it does, if you're using the Python shell, IPython shell or IDLE shell,
-    but if you saved this program as a Python file and ran it, it would flash
-    on for a moment then the program would end and it would turn off.
+And it does, if you're using the Python shell, IPython shell or IDLE shell,
+but if you saved this program as a Python file and ran it, it would flash
+on for a moment then the program would end and it would turn off.
 
-    The following file includes an intentional `pause` to keep the program
-    alive:
+The following file includes an intentional `pause` to keep the program
+alive:
 
-        from gpiozero import LED
-        from signal import pause
+```python
+from gpiozero import LED
+from signal import pause
 
-        led = LED(2)
-        led.on()
-        pause()
+led = LED(2)
+led.on()
+pause()
+```
 
-    Now running the program will stay running, leaving the LED on, until it is
-    forced to quit.
+Now running the program will stay running, leaving the LED on, until it is
+forced to quit.
 
-    Similarly, when setting up callbacks on button presses or other input
-    devices, the program needs to be running for the events to be detected:
+Similarly, when setting up callbacks on button presses or other input
+devices, the program needs to be running for the events to be detected:
 
-        from gpiozero import Button
-        from signal import pause
+```python
+from gpiozero import Button
+from signal import pause
 
-        button = Button(2)
-        button.when_pressed = lambda: print("Button was pressed!")
-        pause()
+button = Button(2)
+button.when_pressed = lambda: print("Button was pressed!")
+pause()
+```