docs(lib/services): Improve comments of the type ServiceRegistry

[EmilGeorgiev]

Changes

Add more comments to the methods and types.

Issues

closes: #4017

[CLAassistant]

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 52.44%. Comparing base (d1ca7aa) to head (74ee529). Report is 118 commits behind head on development.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## development #4018 +/- ## =============================================== + Coverage 50.51% 52.44% +1.92% =============================================== Files 230 248 +18 Lines 29006 25598 -3408 =============================================== - Hits 14653 13425 -1228 + Misses 12856 10541 -2315 - Partials 1497 1632 +135 ```

[dimartiro]

@EmilGeorgiev could you please check the linter errors by executing make lint ?

[EmilGeorgiev]

@EmilGeorgiev could you please check the linter errors by executing make lint ?

Thank you @dimartiro . The PR is updated