Help: Provide full explanation for argument COMMAND in command add_test
The section explaining argument COMMAND is much shorter for command add_test than it is for commands execute_process, add_custom_command, and add_custom_target.
If the handling of COMMAND in add_test differs from all the other three commands mentioned above, then expand this section and explain the difference. Otherwise, provide a link to the full explanation in one the other three doc pages.