docs: remove app from app project

Author: jbogarthyde

packages/angular/cli/commands/add.md

@@ -1,9 +1,9 @@
 Adds the npm package for a published library to your workspace, and configures
-the project in the current working directory (or the default app if you are
+the project in the current working directory (or the default project if you are
 not in a project directory) to use that library, as specified by the library's schematic.
 For example, adding `@angular/pwa` configures your project for PWA support:
 ```bash
 ng add @angular/pwa
 ```
 
-The default app project is the value of `defaultProject` in `angular.json`.
+The default project is the value of `defaultProject` in `angular.json`.