code: function getLastTokenBeforeColon(node) {
              const colonToken = sourceCode.getTokenAfter(node, astUtils.isColonToken);
  
              return sourceCode.getTokenBefore(colonToken);
          }
docs: Starting from the given a 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.