Update readme to clarify slider fractional values

Previous text implied negative values not allowed (they are allowed) and it wasn't clear that fractional numbers were the topic until the example.

Author: clach04

README.md

@@ -538,7 +538,7 @@ In the above example, Sushi and Burgers will be selected by default.
 
 The range slider is used to allow users to select numbers between two values. 
 
-**NOTE** If you set the `step` property to anything less than `1`, 
+**NOTE** If you set the `step` property to a fractional value, 
 it will multiply the final value sent to the watch by 10 to the power of the number of decimal places in the value of `step`.
 Eg: If you set the `step` to `0.25` and the slider has value of `34.5`, the watch will receive `3450`. 
 The reason why this is necessary, is because you can not send floats to the watch via `Pebble.sendAppMessage()`.