🚑 fix bad import

[maxence-lefebvre]

Hi,

As of today, InputStream is the default export of its module and not a named one.

The module CharStreams was trying to load the named one which does not exist.

Test case

console.log(require('antlr4').CharStreams.fromString('test'))

Expected

InputStream {
  name: '<empty>',
  strdata: 'test',
  decodeToUnicodeCodePoints: true,
  _index: 0,
  data: [ 116, 101, 115, 116 ],
  _size: 4
}

Actual

TypeError: InputStream is not a constructor
    at Object.fromString (node_modules\antlr4\src\antlr4\CharStreams.js:19:12)

[ericvergnaud]

Would you mind adding a test? It's a pity we didn't have one to detect that break...

[ericvergnaud]

Thanks!