docs(chips-api/attributes): add examples (#214)

* Update attributes.md to add the Analog Chip Example

* Update attributes.md -- Add Scope and PWM examples

Author: drf5n

docs/chips-api/attributes.md

@@ -43,3 +43,9 @@ Returns the current value of the attribute. `attr` should be a valid attribute h
 ### float attr_read_float(uint32_t attr)
 
 Returns the current value of the attribute. `attr` should be a valid attribute handle, previously returned by `attr_init_float()`.
+
+### Simulator Examples
+
+- [Analog API chip example](https://wokwi.com/projects/330112801381024338) -- Simulates a 0-5V/0-ADC_MAX voltage source. One float attribute and one analog output.
+- [PWM with Scope](https://wokwi.com/projects/354488725362438145) ([github](https://github.com/Dlloydev/Wokwi-Chip-PWM)) -- simulates a PWM input with 1 digital output and three attributes
+- [Scope with PWM](https://wokwi.com/projects/354488725362438145) ([Scope with muliple inputs](https://wokwi.com/projects/359330496025635841)) ([github](https://github.com/Dlloydev/Wokwi-Chip-Scope)) -- Simulates a 4-channel oscilloscope with 4 digital inputs, 4 analog inputs and 4 attributes