urandom: Move example to Move Hub.

Move it do a dedicated example instead of hardcoding it in the module docstring.

Also update changelog for missing previous changes while we are at it.

CHANGELOG.md

@@ -6,11 +6,14 @@
 
 ### Added
 - Documented ``Stop.NONE`` and ``Stop.COAST_SMART``.
+- Documented ``ujson`` module.
 
 ### Changed
 - Changed `PrimeHub.display.image()` to `PrimeHub.display.icon()` and renamed
   its kwarg from `image` to `icon`.
-- Improved presentation and docstrings of the ``ubuiltins`` module.
+- Improved presentation and docstrings of the ``ubuiltins`` and other
+  MicroPython modules
+- Moved the random numbers example for Move Hub to the Move Hub page.
 
 ## 3.2.0b5 - 2022-11-11
 

doc/main/hubs/movehub.rst

@@ -95,3 +95,16 @@ Turning the hub off
 
 .. literalinclude::
     ../../../examples/pup/hub_common/build/system_shutdown_movehub.py
+
+Making random numbers
+**************************************************
+
+The Move Hub does not include the :mod:`urandom` module. If you need random
+numbers in your application, you can try a variation of the following example.
+
+To make it work better, change the initial value of ``_rand`` to something
+that is truly random in your application. You could use the IMU acceleration
+or a sensor value, for example.
+
+.. literalinclude::
+    ../../../examples/pup/hub_movehub/randint_implementation.py

examples/pup/hub_movehub/randint_implementation.py

@@ -0,0 +1,19 @@
+from pybricks.hubs import MoveHub
+
+# Initialize the hub.
+hub = MoveHub()
+
+# Initialize "random" seed.
+_rand = hub.battery.voltage() + hub.battery.current()
+
+
+# Return a random integer N such that a <= N <= b.
+def randint(a, b):
+    global _rand
+    _rand = 75 * _rand % 65537  # Lehmer
+    return _rand * (b - a + 1) // 65537 + a
+
+
+# Generate a few example numbers.
+for i in range(5):
+    print(randint(0, 1000))

src/urandom/__init__.py

@@ -8,18 +8,6 @@
 
 """
 This module implements pseudo-random number generators.
-
-.. note:: This module is not available on the BOOST Move Hub.
-
-    You can make your own random number generator like this instead::
-
-        _rand = hub.battery.voltage() + hub.battery.current()  # seed
-
-        # Return a random integer N such that a <= N <= b.
-        def randint(a, b):
-            global _rand
-            _rand = 75 * _rand % 65537  # Lehmer
-            return _rand * (b - a + 1) // 65537 + a
 """
 
 from typing import Any, Optional, Sequence, overload