Clarifications to documentation

[lettie-roach]

For detailed information about submitting Pull Requests (PRs) to the CICE-Consortium,
please refer to: https://github.com/CICE-Consortium/About-Us/wiki/Resource-Index#information-for-developers

PR checklist

• [ x] Short (1 sentence) summary of your PR:
  Clarifications to documentation
• [ x] Developer(s):
  Lettie Roach
• [ x] Suggest PR reviewers from list in the column to the right.
• @eclare108213 @apcraig
• Please copy the PR test results link or provide a summary of testing completed below.
  No testing
• How much do the PR code changes differ from the unmodified code?
  • [ x] bit for bit
  • different at roundoff level
  • more substantial
• Does this PR create or have dependencies on CICE or any other models?
  • Yes
  • [ x] No
• Does this PR add any new test cases?
  • Yes
  • [x ] No
• Is the documentation being updated? ("Documentation" includes information on the wiki or in the .rst files from doc/source/, which are used to create the online technical docs at https://readthedocs.org/projects/cice-consortium-cice/.)
  • [x ] Yes
  • No, does the documentation need to be updated at a later time?
    • Yes
    • No
• Please provide any additional information or relevant details below:

[apcraig]

I have verified the changes in the readthedocs document, looks OK to me. Just a quick question, should section 2.3 be a subsection of section 2.2? Or does it belong in it's own top level Science section? See https://cice-consortium-icepack--405.org.readthedocs.build/en/405/science_guide/index.html.

[eclare108213]

I think we made a deliberate decision to make this a separate section in the documentation, rather than a subsection of the ITD. It is a generalization of the ITD, but it's a big one. In a sense, the standard ITD is a special case of the FSD code.