otelslog: Add example

[pellared]

Towards open-telemetry/opentelemetry.io#4461

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.8%. Comparing base (d15fe4f) to head (79e41d6).

Additional details and impacted files

@@           Coverage Diff           @@
##            main   open-telemetry/opentelemetry-go-contrib#5355     +/-   ##
=======================================
- Coverage   61.9%   61.8%   -0.1%     
=======================================
  Files        186     186             
  Lines      11388   11388             
=======================================
- Hits        7051    7049      -2     
- Misses      4136    4137      +1     
- Partials     201     202      +1     

see 1 file with indirect coverage changes

[dashpole]

Should the example show how to call slog.SetDefault?

[pellared]

Should the example show how to call slog.SetDefault?

I did not want to do that as many people find global logger as an anti-pattern.