Adding diagnostics to WRF-DART documentation

[braczka]

Description:

Added a more complete diagnostics section to the WRF-DART Tutorial.

Fixes issue

Address issue #543

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] Documentation update

Documentation changes needed?

• [ ] My change requires a change to the documentation.
  • [x] I have updated the documentation accordingly.

Tests

I used diagnostic output from a WRF Tutorial example I have already run. The BASEDIR is located here: /glade/scratch/bmraczka/WRF_DART_Tut4. The analysis_increment.nc, obs_epoch_029.nc and obs_diag_output.nc files, in which I tested the new diagnostic section with are located in ~/output/2017042712/.

Checklist for merging

• [ ] Updated changelog entry
• [x] Documentation updated
• [ ] Update conf.py

Checklist for release

• [ ] Merge into main
• [ ] Create release from the main branch with appropriate tag
• [ ] Delete feature-branch

Testing Datasets

• [ ] Dataset needed for testing available upon request
• [x] Dataset download instructions included
• [ ] No dataset needed

[hkershaw-brown]

note for reviewers, the readthedocs for this pull request can be viewed can be viewed here: https://dart-documentation--544.org.readthedocs.build/en/544/models/wrf/tutorial/README.html#step-6-diagnosing-the-assimilation-results

[braczka]

Latest commits addresses comments by @mjs2369. Also got rid of unrelated and annoying footnote build errors in CLM documentation to partially address issue #546