Class constructor LangiumParser cannot be invoked without 'new'

[dhuebner]

Langium version: 0.0.0
Package name: langium

Steps To Reproduce

1. generate domainmodel example
2. start extension
3. open new *.dmodel file
4. language server crashes

[Info  - 2:49:46 PM] Connection to server got closed. Server will restart.
Debugger listening on ws://127.0.0.1:6009/646ca63e-0fb7-4653-912b-6b90cf296d93
For help, see: https://nodejs.org/en/docs/inspector
/Users/dhuebner/git/langium/examples/domainmodel/out/language-server/generated/parser.js:38
        var _this = _super.call(this, tokens, services) || this;
                           ^

TypeError: Class constructor LangiumParser cannot be invoked without 'new'
    at new Parser (/Users/dhuebner/git/langium/examples/domainmodel/out/language-server/generated/parser.js:38:28)
    at Parser (/Users/dhuebner/git/langium/examples/domainmodel/out/language-server/generated/module.js:8:42)
    at _resolve (/Users/dhuebner/git/langium/packages/langium/lib/dependency-injection.js:71:53)
    at Object.get (/Users/dhuebner/git/langium/packages/langium/lib/dependency-injection.js:37:29)
    at new DefaultDocumentBuilder (/Users/dhuebner/git/langium/packages/langium/lib/documents/document-builder.js:12:32)
    at DocumentBuilder (/Users/dhuebner/git/langium/packages/langium/lib/default-module.js:33:44)
    at _resolve (/Users/dhuebner/git/langium/packages/langium/lib/dependency-injection.js:71:53)
    at Object.get (/Users/dhuebner/git/langium/packages/langium/lib/dependency-injection.js:37:29)
    at Object.startLanguageServer (/Users/dhuebner/git/langium/packages/langium/lib/service/language-server.js:37:48)
    at Object.<anonymous> (/Users/dhuebner/git/langium/examples/domainmodel/out/language-server/main.js:8:11)
[Error - 2:49:47 PM] Connection to server got closed. Server will not be restarted.

[spoenemann]

I fixed that here: c12dea0#diff-a168bebf0b0f41aae53fb09f53f00375c140888da4edac4bad4ebb93390492dd