Update JSDoc on updateWorkspaceFolders when extension host will restart (fix microsoft#165010) (microsoft#165813)

Author: bpasero

src/vscode-dts/vscode.d.ts

@@ -11990,9 +11990,11 @@ declare module 'vscode' {
 		 * by an optional set of `workspaceFoldersToAdd` on the `vscode.workspace.workspaceFolders` array. This "splice"
 		 * behavior can be used to add, remove and change workspace folders in a single operation.
 		 *
-		 * If the first workspace folder is added, removed or changed, the currently executing extensions (including the
-		 * one that called this method) will be terminated and restarted so that the (deprecated) `rootPath` property is
-		 * updated to point to the first workspace folder.
+		 * **Note:** in some cases calling this method may result in the currently executing extensions (including the
+		 * one that called this method) to be terminated and restarted. For example when the first workspace folder is
+		 * added, removed or changed the (deprecated) `rootPath` property is updated to point to the first workspace
+		 * folder. Another case is when transitioning from an empty or single-folder workspace into a multi-folder
+		 * workspace (see also: https://code.visualstudio.com/docs/editor/workspaces).
 		 *
 		 * Use the {@linkcode onDidChangeWorkspaceFolders onDidChangeWorkspaceFolders()} event to get notified when the
 		 * workspace folders have been updated.