style(jshint): curly braces for if statements

Author: andreruffert

src/rangeslider.js

@@ -316,10 +316,10 @@
 
     Plugin.prototype.handleDown = function(e) {
         e.preventDefault();
-        
+
         // Only respond to mouse main button clicks (usually the left button)
-        if (e.button && e.button !== 0) return;
-        
+        if (e.button && e.button !== 0) { return; }
+
         this.$document.on(this.moveEvent, this.handleMove);
         this.$document.on(this.endEvent, this.handleEnd);