Add support for multi declarations in the reflection

[petermasking]

Currently we register only the first declaration in a multi declaration statement as module member:

import { Reflector } from 'jitar-reflection';

const module = Reflector.parse(`const a = 1, b = 2, c = 3;`);
module.hasMember('a'); // true
module.hasMember('b'); // false
module.hasMember('c'); // false

The next step is register the other declarations as well.