Updated description for stress/drought deciduous flag

[mpaiao]

Description:

This fixes the description of parameter fates_phen_stress_decid so it explains how to switch between a "hard" drought deciduous and a semi-deciduous phenology.

Collaborators:

@pollybuotte

Expectation of Answer Changes:

Checklist

If this is your first time contributing, please read the CONTRIBUTING document.

All checklist items must be checked to enable merging this pull request:

Contributor

• The in-code documentation has been updated with descriptive comments
• The documentation has been assessed to determine if updates are necessary

Integrator

• FATES PASS/FAIL regression tests were run
• Evaluation of test results for answer changes was performed and results provided

Documentation

• Technical Note update:
• User's Guide update:

Test Results:

CTSM (or) E3SM (specify which) test hash-tag:

CTSM (or) E3SM (specify which) baseline hash-tag:

FATES baseline hash-tag:

Test Output:

[rgknox]

Straightforward, no issues

[rgknox]

No changes to code or values, so no need to run full regression suite. I did run one test where I generated a new binary parameter file from this and used it in a generic run and the model processed the file just fine. merging