function usedMemberSyntax(node) {
			if (node.specifiers.length === 0) {
				return "none";
			}
			if (node.specifiers[0].type === "ImportNamespaceSpecifier") {
				return "all";
			}
			if (node.specifiers.length === 1) {
				return "single";
			}
			return "multiple";
		}
Gets the used member syntax style.

import "my-module.js" --> none
import * as myModule from "my-module.js" --> all
import {myMember} from "my-module.js" --> single
import {foo, bar} from  "my-module.js" --> multiple
@param {ASTNode} node the ImportDeclaration node.
@returns {string} used member parameter style, ["all", "multiple", "single"]