fs: update jsdoc for filehandle.createWriteStream and appendFile

[pluris]

I updated jsdoc due to inconsistency between documentation and jsdoc.

• filehandle.createWriteStream()
  

  node/doc/api/fs.md

  Lines 336 to 344 in e133e51

  	* `options`{Object}
  	* `encoding`{string} **Default:** `'utf8'`
  	* `autoClose`{boolean} **Default:** `true`
  	* `emitClose`{boolean} **Default:** `true`
  	* `start`{integer}
  	* `highWaterMark`{number} **Default:** `16384`
  	* `flush`{boolean} If `true`, the underlying file descriptor is flushed
  	prior to closing it. **Default:** `false`.
  	* Returns:{fs.WriteStream}

• fs.appendFile()
  

  node/doc/api/fs.md

  Lines 2105 to 2114 in e133e51

  	* `path`{string|Buffer|URL|number} filename or file descriptor
  	* `data`{string|Buffer}
  	* `options`{Object|string}
  	* `encoding`{string|null} **Default:** `'utf8'`
  	* `mode`{integer} **Default:** `0o666`
  	* `flag`{string} See [support of file system `flags`][]. **Default:** `'a'`.
  	* `flush`{boolean} If `true`, the underlying file descriptor is flushed
  	prior to closing it. **Default:** `false`.
  	* `callback`{Function}
  	* `err`{Error}

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CI: https://ci.nodejs.org/job/node-test-pull-request/56855/

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CI: https://ci.nodejs.org/job/node-test-pull-request/56857/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/56858/

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