Update to allow use of 'docs' instead of 'doc' sub-directory

[CarlosMDiaz-NCO]

nws-hpc-standards/docs/standards.rst

Line 715 in d0e8f07

"``doc``","release notes or other documentation"

Suggestion to change this line from 'doc' to 'docs'
This change would make the standards consistent with github expectations. The README.md file only displays correctly on the github page when it is under the root directory, a .github/ directory, or under docs/. Changing doc/ to docs/ will allow developers to keep a README.md file without violating standards by having files under the root directory