Add "ignore standalone" option that disables HLS for files that don't belong to any folder

package.json

@@ -158,6 +158,12 @@
           "default": "",
           "description": "Manually set a language server executable. Can be something on the $PATH or a path to an executable itself. Works with ~, ${HOME} and ${workspaceFolder}."
         },
+        "haskell.ignoreStandalone": {
+          "scope": "resource",
+          "type": "boolean",
+          "default": false,
+          "description": "Don't spawn language servers for stand-alone files (i.e. files that don't belong to any folder)"
+        },
         "haskell.updateBehavior": {
           "scope": "machine",
           "type": "string",

src/extension.ts

@@ -133,8 +133,9 @@ async function activeServer(context: ExtensionContext, document: TextDocument) {
 }
 
 async function activateServerForFolder(context: ExtensionContext, uri: Uri, folder?: WorkspaceFolder) {
+  const ignoreStandalone = workspace.getConfiguration('haskell').ignoreStandalone;
   const clientsKey = folder ? folder.uri.toString() : uri.toString();
-
+  if (!folder && ignoreStandalone) return;
   // If the client already has an LSP server for this uri/folder, then don't start a new one.
   if (clients.has(clientsKey)) {
     return;