Update lsp to have set root path

compiler/NubLang.LSP/Program.cs

@@ -18,17 +18,7 @@ var server = await LanguageServer.From(options => options
     .WithHandler<HoverHandler>()
     .WithHandler<CompletionHandler>()
     .WithHandler<DefinitionHandler>()
-    .OnInitialize((server, request, ct) =>
-    {
-        var workspaceManager = server.GetRequiredService<WorkspaceManager>();
-
-        if (request.RootPath != null)
-        {
-            workspaceManager.Init(request.RootPath);
-        }
-
-        return Task.CompletedTask;
-    })
+    .WithHandler<SetRootPathCommandHandler>()
 );
 
 await server.WaitForExit;