compare(otherSelector) {
		return (
			this.attributeCount - otherSelector.attributeCount ||
			this.identifierCount - otherSelector.identifierCount ||
			(this.source <= otherSelector.source ? -1 : 1)
		);
	}
Compares this selector's specifity to another selector for sorting purposes.
@param {ESQueryParsedSelector} otherSelector The selector to compare against
@returns {number}
a value less than 0 if this selector is less specific than otherSelector
a value greater than 0 if this selector is more specific than otherSelector
a value less than 0 if this selector and otherSelector have the same specificity, and this selector <= otherSelector alphabetically
a value greater than 0 if this selector and otherSelector have the same specificity, and this selector > otherSelector alphabetically