ww3_doxy_tmpl.md: clarify MODULE markup

[MatthewMasarik-NOAA]

Pull Request Summary

Clarifies the doxygen markup specific to Fortran MODULE.

Description

Provide a detailed description of what this PR does.

• Corrects the doxygen markup that is needed for the MODULE Fortran code unit. The previous doxygen fix PR clarified that the @param tag was not used for MODULE variables. In hindsight, it should have also been clarified that there are two sections for it: a header that stays above the MODULE line, and then the inline variable documentation that go below it.

What bug does it fix, or what feature does it add?

• Addresses a confusing part of the header template file, docs/ww3_doxy_tmpl.md.

Is a change of answers expected from this PR?

• No. Only the header template file has been changed.

Please also include the following information:

• Add any suggestions for a reviewer

  • Thanks to @ukmo-ccbunney who encountered this first.

• Mention any labels that should be added:

  • documentation.

• Are answer changes expected from this PR? Please describe the changes and the reason why in addition to which of the following labels would apply:

  • No answers are expected to change. No source code has been edited.

Issue(s) addressed

• Please list any issues associated with this PR, including those the PR will fix/close. For example:
  • N/A.

Commit Message

ww3_doxy_tmpl.md: clarify MODULE markup

Check list

• Branch is up to date with the authoritative repository (NOAA-EMC) develop branch.
• Checked the checklist for a developer submitting to develop.
• [na] If a version number update is required, checked the updating version number checklist.
• [na] If a new feature was added, a regression test for testing the new feature is added.

Testing

• How were these changes tested?
  • No source code changes, so nothing to test.
• Are the changes covered by regression tests? (If not, why? Do new tests need to be added?)
  • No. Not required for documentation.
• Have the matrix regression tests been run (if yes, please note HPC and compiler)?
  • N/A. See above.
• Please provide the summary output of matrix.comp (matrix.Diff.txt, matrixCompFull.txt and matrixCompSummary.txt):
  • N/A. See above.
• Please indicate the expected changes in the regression test output (Note the known list of non-identical tests).
  • No changes.
• Please provide the summary output of matrix.comp (matrix.Diff.txt, matrixCompFull.txt and matrixCompSummary.txt):
  • N/A. See above.

[JessicaMeixner-NOAA]

No regtests run as it's just a doxygen file update