This new processor, named `mergeOverriddenImplementation`, allows Dgeni to produce correct documentation for symbols with overridden exported constructors. For example, in the following example, the implementation documentation will be used, including the constructor signature:
```
export const Foo: FooCtor = FooImpl as FooCtor;
```
This is a major improvement over the current situation, in which no constructor signature is documented whatsoever.
PR Close#44689
