Improve clarity of deprecation warning for coloring key renames

[Copilot]

PR summary from human (Cornelius)

Improve clarity of colorings deprecation warning.

Resolves #1882

No need for Changelog entry as it's a trivial change.

Copilot auto generated PR message

The deprecation warning for coloring key renames was unclear about what action users needed to take. The original message `"DEPRECATED: [config file] renaming coloring 'authors' to 'author'"` left users confused about whether they needed to change their configuration or if this was just informational.

Before (unclear):

DEPRECATED: [config file] renaming coloring 'authors' to 'author'

After (clear and actionable):

DEPRECATED: [config file] Found deprecated coloring key 'authors'. This has been automatically renamed to 'author'. Please update your auspice config file to use 'author' instead of 'authors' to avoid this warning.

The improved message clearly explains:

1. What was found: A deprecated coloring key
2. What automatic action was taken: The key was renamed automatically
3. What the user should do: Update their auspice config file to use the new key name

This change applies to both deprecated coloring keys:

• authors → author
• numdate → num_date

The implementation focuses solely on improving the warning message clarity, and all existing functionality remains unchanged.

Fixes #1882.

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[corneliusroemer]

@copilot no need for a test here, please remove the test you added

[Copilot]

@copilot no need for a test here, please remove the test you added

Removed the test as requested. The test file has been reverted to its original state while keeping the improved deprecation warning message. (d4db7fd)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.60%. Comparing base (e8b4d47) to head (6fc1921).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1883   +/-   ##
=======================================
  Coverage   73.60%   73.60%           
=======================================
  Files          80       80           
  Lines        8802     8802           
  Branches     1799     1799           
=======================================
  Hits         6479     6479           
  Misses       2019     2019           
  Partials      304      304           

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[tsibley]

When I saw the "author" of this PR in email, I was curious to see the PR, how it evolved over time, what the interaction looked like, etc. Given all the interaction and faffing about required for it, ITSM that there's no way this was faster or easier than just making the change directly. @corneliusroemer What's your thought here?