New Issue: chpldoc doesn't like 'docs' as a directory name for '--save-sphinx'

16904, “bradcray”, “chpldoc doesn’t like ‘docs’ as a directory name for ‘–save-sphinx’”, “2021-01-05T19:21:30Z”

When trying to debug a problem in the .rst generated by chpldoc (as part of working through #16903), my instinct was to use the --save-sphinx flag, and for whatever reason, the first directory name that came to mind for me was docs. However, when using --save-sphinx docs results in:

Warning, treated as error:
html_static_path entry '_static' is placed inside outdir
error: building html output from chpldoc sphinx project

It took me awhile to realize that docs/ is a special name for chpldoc and that that was the cause of the problem. Better would be to have chpldoc report an error when trying to use this directory name with the --save-sphinx flag.