Fix acl module doc and  error messages

- Fix typos in module doc
- Provide clearer error message when entry and etype are both missing
Whitespace fixes in incompatible param check

- Remove extra whitespace in conditional that checks if etype, entity or
  permissions are also set when entry is set.
Merge pull request #6515 from lotia/fix-acl-doc-and-error

Fix acl doc and error