Servo lib docs (#1686)

* Servos extension ref docs

* fix param name

libs/servo/docs/reference/servos/run.md

@@ -0,0 +1,32 @@
+# run
+
+Tell a continuous rotation servo to turn at a certain speed.
+
+```sig
+servos.P0.run(50)
+```
+
+A continuous rotation servo can turn both clockwise and counter-clockwise. They rotate at a speed from stopped to maximum rotation speed. Normally, a continuous rotation servo interprets  an angle value as a speed value. But, by using ``||servos:run||`` though, you can use a speed percentage value to turn the servo from no speed to full speed (`0` to `100` percent). Also, for clockwise rotation, the speed value used is a positive number, speed > 0. If you want to turn the servo in the other direction (counter-clockwise), use a negative percentage value.
+
+## Parameters
+
+* **speed**: a [number](types/number) which is the percentage (`0` to `100`) of speed to turn the servo at. Use a positive value (speed > 0) to go clockwise and use a negative value to turn counter-clocwise.
+
+## Example
+
+Connect a servo to pin `P0`. Rotate the servo clockwise at `75` percent of full speed. Wait `3` seconds and then stop the servo.
+
+```blocks
+servos.P0.run(75)
+basic.pause(3000)
+servos.P0.run(0)
+```
+
+## See also
+
+[set pulse](/reference/servos/set-pulse),
+[set angle](/reference/servos/set-angle)
+
+```package
+servo
+```