Bugfix #2730 develop SI_BCU

[JohnHalleyGotway]

Expected Differences

One line bugfix to correct a typo in the CNT column names written to *_cnt.txt files from Point-Stat and Grid-Stat. One instance of SI_BCL should really be SI_BCU. Note that this column name appears in:

1. data/table_files/met_header_columns*
2. internal/test_unit/hdr/met*
3. MET User's Guide
4. series_analysis.cc
5. stat_columns.cc
6. stat_column_defs.h

I checked all those spots and only found the typo in the last one.

• Do these changes introduce new tools, command line arguments, or configuration file options? [No]
  
  If yes, please describe:
  

• Do these changes modify the structure of existing or add new output data types (e.g. statistic line types or NetCDF variables)? [Yes]
  
  If yes, please describe:
  
  Fixes a typo in the CNT line type.

Pull Request Testing

• Describe testing already performed for these changes:
  
  None

• Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
  
  Monitor GHA testing run to see if any differences are flagged. Differences will now exist in the *_cnt.txt output files. So diffing them will be relatively slow because the file diff command won't suffice. However I'm really not sure how the column name header diff will be treated. So the diff step may or may not fail.

• Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [No]
  None needed.

• Do these changes include sufficient testing updates? [No]
  None needed.

• Will this PR result in changes to the test suite? [Yes]
  
  If yes, describe the new output and/or changes to the existing output:
  
  See above, but I'm not sure whether or not this diff will be flagged.
  Regardless, we should update the truth dataset to get accept this change so that we don't waste time diffing *_cnt.txt files anymore.

• Please complete this pull request review by [Friday 11/10/23].
  

Pull Request Checklist

See the METplus Workflow for details.

• Review the source issue metadata (required labels, projects, and milestone).
• Complete the PR definition above.
• Ensure the PR title matches the feature or bugfix branch name.
• Define the PR metadata, as permissions allow.
  Select: Reviewer(s) and Development issue
  Select: Milestone as the version that will include these changes
  Select: Coordinated METplus-X.Y Support project for bugfix releases or MET-X.Y.Z Development project for official releases
• After submitting the PR, select the ⚙️ icon in the Development section of the right hand sidebar. Search for the issue that this PR will close and select it, if it is not already selected.
• After the PR is approved, merge your changes. If permissions do not allow this, request that the reviewer do the merge.
• Close the linked issue and delete your feature or bugfix branch from GitHub.

[georgemccabe]

I see that the only differences flagged are in stat_analysis.out and involve changing SI_BCL SI_BCL to SI_BCL SI_BCU which reflects the code change. The MET diff tests didn't flag any other differences, but they might get picked up by the METplus use case diff tests after this PR is merged. If this aligns with your expected differences, then I approve this PR.