Only one h1 is allowed per document, and this is provided by the template.
So we cannot have any h1 tags (or `#` markdown shorthand) in any API docs.
Closes#16193
fixes#12869fixes#12889fixes#13885fixes#13870
Before this change there was a single injector tree.
Now we have 2 injector trees, one for the modules and one for the components.
This fixes lazy loading modules.
See the design docs for details:
https://docs.google.com/document/d/1OEUIwc-s69l1o97K0wBd_-Lth5BBxir1KuCRWklTlI4
BREAKING CHANGES
`ComponentFactory.create()` takes an extra optional `NgModuleRef` parameter.
No change should be required in user code as the correct module will be used
when none is provided
DEPRECATIONS
The following methods were used internally and are no more required:
- `RouterOutlet.locationFactoryResolver`
- `RouterOutlet.locationInjector`
