Defeat many warnings and related fixes building documentation

* Mask various CLI options with exclamation marks (!)
* Correct link to CLI section in zipapp
* Make CLI section label in timeit less ambiguous

The following warnings from unittest remain. Ideally they should be linked to the Python CLI documentation, but this does not seem possible because the “unittest” documentation defines its own CLI options.

Doc/library/unittest.rst:1965: WARNING: unknown option: -Wd
Doc/library/unittest.rst:1965: WARNING: unknown option: -Wa
Doc/library/unittest.rst:2051: WARNING: unknown option: -W