Since commit 6e58a01f4e (Tutorial: Update step 6 style, 2022-10-06) the
`literalinclude` included an extra comment from step 6 instructions.
Fix the include bounds to remove the extra text.
Small changes to the text and CMake code for the fourth step of the
tutorial:
* Remove parameter from endfunction call
* Standardize on "binary directory" for test location
* Add additional information about a Release build.
Issue: #22663
Extend the change from commit 9e5bbb69ea (Tutorial: Add captions for
code blocks, 2021-06-11) to also add a Sphinx named target to code
blocks. Name each target after the change the code block makes.
