Fix API incompatobilities in latest o.e.lsp4e (v. >= 0.17)

[vrubezhny]

No description provided.

[mickaelistria]

This change looks very good. Anything particular you'd like me to give more attention? If not, the sooner we merge, the better.

[vrubezhny]

This change looks very good. Anything particular you'd like me to give more attention? If not, the sooner we merge, the better.

@mickaelistria JUnit test TestTypeScript.testHTMLinTSXFile() is quite unstable failing by time out expired while trying to collect language servers for document. From one side - it's only a test that just started an editor, so the LS needs some time to initialize, so I've used 500ms timeout here, but we have a similar code collecting the LSs in AssociateGrammarHandler.executeServerCommand - I've put 100ms timeout here - in theory at least one LS is to be initialized and active at this point, but I still in doubt on what should be the correct timeout value here?

[mickaelistria]

This test is working on the Jenkins build for this PR, so I woudn't worry about it. If it is the only concern, then I believe this PR is good to merge now.

[vrubezhny]

Well. Just well be watching for UnsupportedOperationException("No language server has registered to handle command XXX")-like exceptions then.