docs(all): add commits convention description in CONTRIBUTING.rst (#9905

)

* docs: add commits convention description in CONTRIBUTING.rst

* docs: remove extra empty line in CONTRIBUTING.rst

* docs: remove excess lines in CONTRIBUTING.rst

CONTRIBUTING.rst

@@ -151,6 +151,15 @@ Exceptions to PEP8:
   "Function-Under-Test"), which is PEP8-incompliant, but more readable.
   Some also use a local variable, ``MUT`` (short for "Module-Under-Test").
 
+*************************
+Commit Message Convention
+*************************
+
+We use `Conventional Commits`_ as a convention for writing commit messages.
+It provides an easy set of rules for creating an explicit commit history.
+
+.. _Conventional Commits: https://www.conventionalcommits.org/
+
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 Running System Tests
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