print async thread pinned cores

[Nibanovic]

_{The tinyest of PRs}

following this one and this review comment.
as part of thread renaming PR accross ros2_control and realtime_tools

Just prints the PCU cores we pinned on.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.39%. Comparing base (0e0bca0) to head (cc62adf).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #551      +/-   ##
==========================================
+ Coverage   84.37%   84.39%   +0.02%     
==========================================
  Files          17       17              
  Lines        1427     1429       +2     
  Branches      138      138              
==========================================
+ Hits         1204     1206       +2     
  Misses        134      134              
  Partials       89       89              

Flag	Coverage Δ
unittests	84.39% <100.00%> (+0.02%)	⬆️

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Files with missing lines	Coverage Δ
.../include/realtime_tools/async_function_handler.hpp	72.60% <100.00%> (+0.25%)	⬆️

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