Add TeamCity test directives

[timbavtbc]

This relates to issue 421 - about using the test-specific directives like ##teamcity[testSuiteStarted ... ] instead of just ##teamcity[message] directives.

It occurs to me that this should probably be a separate renderer: some folks might prefer the message based one, and to use junit or some other test integration for counting tests.

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 17 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.48%. Comparing base (87c5557) to head (3c98c3d).

Files with missing lines	Patch %	Lines
...ces/XcbeautifyLib/Renderers/TeamCityRenderer.swift	75.00%	17 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #431      +/-   ##
==========================================
- Coverage   91.96%   91.48%   -0.48%     
==========================================
  Files          17       17              
  Lines        2538     2596      +58     
==========================================
+ Hits         2334     2375      +41     
- Misses        204      221      +17     

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