ionic generate: Unknown option: '--change-detection'

**Description:**

One of the examples in the [Ionic Generate docs](https://ionicframework.com/docs/cli/commands/generate#examples) is `ionic generate component login-form --change-detection=OnPush` but executing that exact command returns an error:

```
ionic generate component login-form --change-detection=OnPush
=> Unknown option: '--change-detection'
```

The same happens when trying to use some other options:

```
ionic generate component login-form --view-encapsulation=None
=> Unknown option: '--view-encapsulation'
```

**Steps to Reproduce:**

In any Ionic Angular project execute the following command: `ionic generate component login-form --change-detection=OnPush`

**Output:**

```
ionic generate component login-form --change-detection=OnPush
=> Unknown option: '--change-detection'
```

**My `ionic info`:**

```
Ionic:

Ionic CLI : 6.11.8
Ionic Framework : @ionic/angular 5.3.2
@angular-devkit/build-angular : 0.1000.8
@angular-devkit/schematics : 10.0.8
@angular/cli : 10.0.8
@ionic/angular-toolkit : 2.3.3

Cordova:

Cordova CLI : 9.0.0 (cordova-lib@9.0.1)
Cordova Platforms : android 9.0.0, ios 5.1.1
Cordova Plugins : cordova-plugin-ionic-keyboard 2.2.0, cordova-plugin-ionic-webview 5.0.0, (and 23 other plugins)

Utility:

cordova-res : 0.15.1
native-run (update available: 1.0.0) : 0.2.6

System:

Android SDK Tools : 26.1.1
ios-deploy : 1.9.4
ios-sim : 8.0.2
NodeJS : v10.16.2
npm : 6.9.0
OS : macOS Catalina
Xcode : Xcode 11.6 Build version 11E708
```

Start with the Ionic Generate documentation examples linked in the issue and compare the documented options with the reported CLI behavior. Update the examples so they no longer advertise unsupported options, then verify that the commands shown in the documentation are valid.

Scritto dal modello di indicizzazione a partire dal testo della issue.