Update hello_effects.adoc

Modified the emitter parameter table column widths to 10,50,15,25.

src/docs/asciidoc/jme3/beginner/hello_effects.adoc

@@ -235,7 +235,7 @@ emitter.setShape(new EmitterPointShape(Vector3f.ZERO));
 ----
 
 You create different effects by changing the emitter parameters: 
-[cols="15,45,15,25", options="header"]
+[cols="10,50,15,25", options="header"]
 |===
 
 <a| Parameter