Support for workspace/didChangeWatchedFiles

[angelozerr]

In our Qute LS we need workspace/didChangeWatchedFiles support.

With Qute you can write a template like this:

{#include foo.html}
{/include}

At this step, It reports an error to foo.html which doesn't exists.

If you create the foo.html, LSP4E should send workspace/didChangeWatchedFiles notfication with a FileEvent

• uri = foo.html
• type = Created

The Qute LS reacts on this event to retrigger validation (the template which include foo.html will not be on error).

Today we manage this usecase by creating a FileSystemWatcher on Qute LS side but it is not really performant (because we need to create a Watcher per sub directories).

//cc @sbouchet please note this support is very important for JBoss Quarkus because Qute LS has a bug when the folder src/main/resources/templates doesn't exist and freeze the Qute language server. See redhat-developer/quarkus-ls#931