`ng_module` will now include an `src/r3_symbol.d.ts` when compiling the core package under `ngc` togather with `dts bundling`, This is due that `ngcc` relies on this file to be present, but the `r3_symbols` file which is not part of our public api.
With this change, we can now ship an addition dts file which is flattened.
PR Close#28884
This enabled dts flattening in the final distrubutable package.
Notes:
- For the time being this is an opt-in feature via the `ng_module` attribute `bundle_dts`, however in the near future this will be turned on by default.
- This only supports the legacy compiler `ngc`, as `ngtsc` emits namespaced imports `import * as __` from local modules which is not supported for the time being by API Extractor. See: https://github.com/Microsoft/web-build-tools/issues/1029
Ref: TOOL-611
PR Close#28588
Alex Eagle
Alan
Greg Magolan