docs: add docs & hints on --strict flag

Author: micalevisk

content/cli/usages.md

@@ -34,6 +34,7 @@ Creates and initializes a new Nest project. Prompts for package manager.
 | `--package-manager [package-manager]` | Specify package manager. Use `npm`, `yarn`, or `pnpm`. Package manager must be installed globally.<br/> Alias: `-p` |
 | `--language [language]`               | Specify programming language (`TS` or `JS`).<br/> Alias: `-l`                                                       |
 | `--collection [collectionName]`       | Specify schematics collection. Use package name of installed npm package containing schematic.<br/> Alias: `-c`     |
+| `--strict`                            | Start the project with the following TypeScript compiler flags enalbed: `strictNullChecks`, `noImplicitAny`, `strictBindCallApply`, `forceConsistentCasingInFileNames`, `noFallthroughCasesInSwitch` |
 
 #### nest generate
 

content/first-steps.md

@@ -21,6 +21,8 @@ $ npm i -g @nestjs/cli
 $ nest new project-name
 ```
 
+> info **Hint** If you want to create a new project with few flags of TypeScript's strict mode enabled, add the option `--strict` on `new` command. We highly recommend that! More on this option [here](./cli/usages).
+
 The `project-name` directory will be created, node modules and a few other boilerplate files will be installed, and a `src/` directory will be created and populated with several core files.
 
 <div class="file-tree">

content/introduction.md

@@ -23,6 +23,8 @@ $ npm i -g @nestjs/cli
 $ nest new project-name
 ```
 
+> info **Hint** If you want to create a new project with few flags of TypeScript's strict mode enabled, add the option `--strict` on `new` command. We highly recommend that! More on this option [here](./cli/usages).
+
 #### Alternatives
 
 Alternatively, to install the TypeScript starter project with **Git**: