Prettier 2.8.2
Playground link

Input:

<app-test/>

Output:

SyntaxError: Only void and foreign elements can be self closed "app-test" (1:1)
> 1 | <app-test/>
    | ^^^^^^^^^
  2 |

Expected behavior:
In Angular 15.1.0 developers are allowed to use self closed tags for custom elements angular/angular#48535
Prettier should support this feature