- Add @angular/core in detecting angular to set the web-angularjs minor
mode
- At the same time set the web-mode-engine to "angular" so that
`format-all` uses prettier to format ionic `*.page.html` files in
addition to `*.component.html` files.
When `format-all` sees the web-mode-engine is set to "angular", it
applies `prettier` as opposed to `html-tidy`, as `tidy` doesn't
recognise angular component tags and hence errors out. The current
web-mode only sets the engine to "angular" for "*.components.html".
However, ionic angular uses file names such as "*.page.html", setting
engine will apply prettier to these html fils.