Fix Scala.JS example in README (alexarchambault#237)

Co-authored-by: Alexandre Archambault <[email protected]>

Author: Sciss

README.md

@@ -68,24 +68,20 @@ import plotly._, element._, layout._, Plotly._
 
 Then define plots like
 ```scala
-val x = 0.0 to 10.0 by 0.1
+val x = (0 to 100).map(_ * 0.1)
 val y1 = x.map(d => 2.0 * d + util.Random.nextGaussian())
 val y2 = x.map(math.exp)
 
 val plot = Seq(
-  Scatter(
-    x, y1, name = "Approx twice"
-  ),
-  Scatter(
-    x, y2, name = "Exp"
-  )
+  Scatter(x, y1).withName("Approx twice"),
+  Scatter(x, y2).withName("Exp")
 )
 ```
 and plot them with
+
 ```scala
-plot.plot(
-  title = "Curves"
-)
+val lay = Layout().withTitle("Curves")
+plot.plot("plot", lay)  // attaches to div element with id 'plot'
 ```