docs: Prefer Jinja2 "set" directive to default_parameter_xxx in examples

The "set" directive is more flexible and easier to understand.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/sample-raspberry-pi.cfg

@@ -30,13 +30,13 @@ i2c_bus: i2c.1
 htu21d_hold_master: False
 
 [gcode_macro QUERY_ENCLOSURE]
-default_parameter_SENSOR: htu21d enclosure_temp
 gcode:
+    {% set sensor = printer["htu21d enclosure_temp"] %}
     {action_respond_info(
         "Temperature: %.2f C\n"
         "Humidity: %.2f%%" % (
-            printer[SENSOR].temperature,
-            printer[SENSOR].humidity))}
+            sensor.temperature,
+            sensor.humidity))}
 
 # Example 3:Using a pin on another gpiochip connected to the RPi
 # (in this case on an MCP23017)