Remove sphinx internal docs links from readme

README.rst

@@ -59,7 +59,7 @@ together:
     pause()
 
 You can advance to using the declarative paradigm along with provided
-:doc:`source tools <api_tools>` to describe the behaviour of devices and their
+ to describe the behaviour of devices and their
 interactions:
 
 .. code:: python
@@ -76,7 +76,9 @@ interactions:
 
     pause()
 
-See the chapter on :doc:`Source/Values <source_values>` for more information.
+See the chapter on `Source/Values`_ for more information.
+
+.. _Source/Values: https://gpiozero.readthedocs.io/en/stable/source_values.html
 
 The library includes interfaces to many simple everyday components, as well as
 some more complex things like sensors, analogue-to-digital converters, full
@@ -91,14 +93,16 @@ Pin factories
 GPIO Zero builds on a number of underlying pin libraries, including `RPi.GPIO`_
 and `pigpio`_, each with their own benefits. You can select a particular pin
 library to be used, either for the whole script or per-device, according to your
-needs. See the section on :ref:`changing the pin factory
-<changing-pin-factory>`.
+needs. See the section on `changing the pin factory`_.
 
-.. _RPi.GPIO: https://pypi.org/project/RPi.GPIO/
+.. _RPi.GPIO: https://pypi.org/project/RPi.GPIO
 .. _pigpio: https://pypi.org/project/pigpio
+.. _changing the pin factory: https://gpiozero.readthedocs.io/en/stable/api_pins.html#changing-the-pin-factory
 
 A "mock pin" interface is also provided for testing purposes. Read more about
-this in the section on :ref:`mock pins <mock-pins>`.
+this in the section on `mock pins`_.
+
+.. _mock pins: https://gpiozero.readthedocs.io/en/stable/api_pins.html#mock-pins
 
 Installation
 ============