Demonstrate how to include other headers extension to the C++ public header artifacts

There is no convenience for this yet, however, it is possible to do this by configuring the `cppHeaders` tasks directly. Headers sometimes have extension such as `.hpp` or `.hxx`. C++ inline implementation are sometimes included as separated files such as `.inl`.

Start by reading the cppHeaders task configuration referenced in the issue and identify how public header artifacts are assembled. Document an example covering .hpp, .hxx, and .inl files, with completion shown by a clear configuration example for including these extensions.

Written by the indexing model from the issue text.