Feat/create book (#9159)

* added secondary action

* create book command

* open as untitled

* create toc.yml and update title

* added comments

* throw error if filenames have unsupported chars

* update prompt message

* remove the toLocaleLower

* added await

* moced createbookpath out of the command handler

* removed tolocalelower and added comments

* moved the formatting and file handling code from core to notebook

* fixes for contents with folders

* collapse the code cell

* remove output

* reused existing command to open book

* comment typu and added await

extensions/notebook/src/book/bookTreeView.ts

@@ -112,8 +112,7 @@ export class BookTreeViewProvider implements vscode.TreeDataProvider<BookTreeIte
 		try {
 			if (this._openAsUntitled) {
 				this.openNotebookAsUntitled(resource);
-			}
-			else {
+			} else {
 				let doc = await vscode.workspace.openTextDocument(resource);
 				vscode.window.showTextDocument(doc);
 			}