BREAKING CHANGES:
- `#` and `var` are not supported any more in expressions, use `let`,
- `var-<name>` could not be used any more on templates, use `let-<name>`,
- `var-<name>` could not be used any more to create a reference, use `ref-<name>`.
BREAKING CHANGE: Animations defined using an at-symbol prefix that are
not property bound are now invalid.
```html
<!-- this is now invalid -->
<div @flip="flipState"></div>
<!-- change that to -->
<div [@flip]="flipState"></div>
```
BREAKING CHANGE: Animations that are not bound using the at-symbol
prefix using `animate-` must now be preixed using `bind-animate-`.
```html
<!-- this is now invalid -->
<div animate-flip="flipState"></div>
<!-- is valid now -->
<div bind-animate-flip="flipState"></div>
```
Closes#10825
