docs(comments): fix inline comments to match code

[iainsproat]

• The comments for schema and errorCode parameters are now relevant.
• The function descriptions do not unnecessarily refer to Cookies if they are not processing Cookies.
• The documented default value for errorMessage parameter now matches the default in the function itself.

Closes # .

Checklist:

• [ ] issue number linked above after pound (#)
  • replace "Closes " with "Contributes to" or other if this PR does not close the issue
• [x] checking not applicable
• [x] testing not applicable
• [x] screenshot not applicable