docs(openapi): handle mapped-types and add build steps

Closes #1959

Author: shoaib30

content/openapi/cli-plugin.md

@@ -53,6 +53,8 @@ export class CreateUserDto {
 }
 ```
 
+> info **Hint** When using `PartialType, OmitType, PickType, IntersectionType` in dtos import them from `@nestjs/swagger` instead of `@nestjs/mapped-types` for the plugin to pick up the schema
+
 The plugin adds appropriate decorators on the fly based on the **Abstract Syntax Tree**. Thus you won't have to struggle with `@ApiProperty` decorators scattered throughout the code.
 
 > info **Hint** The plugin will automatically generate any missing swagger properties, but if you need to override them, you simply set them explicitly via `@ApiProperty()`.
@@ -184,6 +186,25 @@ export interface PluginOptions {
   </tr>
 </table>
 
+On the first run and when ever plugin options are changed. Delete `/dist` folder and build the application using
+
+```bash
+$ nest build
+```
+
+Or you can configure `package.json` with the following scripts
+
+```json
+"prebuild": "rimraf dist",
+"build": "nest build",
+```
+
+and run it using
+
+```bash
+$ npm run build
+```
+
 If you don't use the CLI but instead have a custom `webpack` configuration, you can use this plugin in combination with `ts-loader`:
 
 ```javascript