code: function report(node, startOffset, character) {
              context.report({
                  node,
                  loc: sourceCode.getLocFromIndex(sourceCode.getIndexFromLoc(node.loc.start) + startOffset),
                  message: "Unnecessary escape character: \\{{character}}.",
                  data: { character }
              });
          }
docs: Reports a node
  @param {ASTNode} node The node to report
  @param {number} startOffset The backslash's offset from the start of the node
  @param {string} character The uselessly escaped character (not including the backslash)
  @returns {void}