fix Template substitution of CtExecutableReference#simpleName

[pvojtechovsky]

There was not possible to substitute name of invoked method.

Example template:

public class InvocationTemplate extends ExtensionTemplate {

	IFace iface;
	
	void invoke() {
//this method name was not substituted. This PR fixes it
		iface.$method$();
	}
	
	@Local
	public InvocationTemplate(CtTypeReference<?> ifaceType, String methodName) {
		this.ifaceType = ifaceType;
		this.methodName = methodName;
	}

	@Parameter("IFace")
	CtTypeReference<?> ifaceType;
	
	@Parameter("$method$")
	String methodName;

	@Local
	interface IFace {
		void $method$();
	}
}

[monperrus]

contract: the template engine supports substitution of method names in method calls.

[monperrus]

// iface.$method$() becomes iface.hashCode()

[monperrus]

interesting!

it looks more like a new feature than a fix :-)

[monperrus]

Thanks Pavel! you can be proud of being the first external contributor contributing to the awesome yet complex template engine!!!