Fix formatting in axis example

Signed-off-by: Sachin Pangal <151670745+Sachinn-64@users.noreply.github.com>

Author: Sachinn-64

lib/node_modules/@stdlib/plot/vega/axis/ctor/examples/index.js

@@ -22,7 +22,7 @@ var Axis = require( './../lib' );
 
 var axis = new Axis({
 	'scale': 'xScale',
-	'orient': 'bottom',
+	'orient': 'bottom'
 });
 
 console.log( axis.toJSON() );