Support JSXElement. (no parse)

[koba04]

Currently, an error occurs when I target files including jsx syntax like below.

import React from 'react';

class App extends React.Component {
  render() {
    return <div>Hello</div>;
  }
}

• error trace

Error: Unknown node type JSXElement.
    at Controller.traverse (/Users/koba04/project/node_modules/esdoc/node_modules/estraverse/estraverse.js:515:31)
    at Object.traverse (/Users/koba04/project/node_modules/esdoc/node_modules/estraverse/estraverse.js:707:27)
    at Function.findPathInImportDeclaration (/Users/koba04/project/node_modules/esdoc/out/src/Util/ASTUtil.js:60:31)
    at ClassDoc._resolveLongname (/Users/koba04/project/node_modules/esdoc/out/src/Doc/AbstractDoc.js:943:51)
    at ClassDoc._extends (/Users/koba04/project/node_modules/esdoc/out/src/Doc/ClassDoc.js:137:29)
    at ClassDoc._apply (/Users/koba04/project/node_modules/esdoc/out/src/Doc/ClassDoc.js:53:23)
    at ClassDoc.AbstractDoc (/Users/koba04/project/node_modules/esdoc/out/src/Doc/AbstractDoc.js:54:10)
    at new ClassDoc (/Users/koba04/project/node_modules/esdoc/out/src/Doc/ClassDoc.js:36:20)
    at DocFactory._createDoc (/Users/koba04/project/node_modules/esdoc/out/src/Factory/DocFactory.js:320:14)
    at DocFactory._traverseComments (/Users/koba04/project/node_modules/esdoc/out/src/Factory/DocFactory.js:250:24)

This pull request is for fixing it.
This doesn't include parsing JSX tree.

[h13i32maru]

@koba04 Thank you this PR 😄

[koba04]

thank you! 😊