add types to all the buttons in the angular.io examples to encourage
the best practice of always including a type per button (regardless
to whether it is in a form or now)
PR Close#44557
DEPRECATION:
The template prefixes `bind-`, `on-`, `bindon-`, and `ref-` have been deprecated
in v13. Templates should use the more widely documented syntaxes for binding and references:
* `[input]="value"` instead of `bind-input="value"`
* `[@trigger]="value"` instead of `bind-animate-trigger="value"`
* `(click)="onClick()"` instead of `on-click="onClick()"`
* `[(ngModel)]="value"` instead of `bindon-ngModel="value"`
* `#templateRef` instead of `ref-templateRef`
PR Close#43671
Fixes#31186. This commit adds more context about the behavior
of template reference variables in nested templates and moves
doc into concepts section.
PR Close#31195
