Currently, would-be binding attributes that are missing binding names
are not parsed as bindings, and fall through as regular attributes. In
some cases, this can lead to a runtime error; trying to assign `#` as a
DOM attribute in an element like in `<div #></div>` fails because `#` is
not a valid attribute name.
Attributes composed of binding prefixes but not defining a binding
should be considered invalid, as this almost certainly indicates an
unintentional elision of a binding by the developer. This commit
introduces error reporting for attributes with a binding name prefix but
no actual binding name.
Closes https://github.com/angular/vscode-ng-language-service/issues/293.
PR Close#34595