function getLastTokenBeforeColon(node) {
			const colonToken = getNextColon(node);

			return sourceCode.getTokenBefore(colonToken);
		}
Starting from the given node (a property.key node here) looks forward
until it finds the last token before a colon punctuator and returns it.
@param {ASTNode} node The node to start looking from.
@returns {ASTNode} The last token before a colon punctuator.