doc: clarify that pre-commit is optional

Change-Id: Id904304da6c8b300fbdf151089bfc95666bdaebe

Author: sbauza

doc/source/contributor/development-environment.rst

@@ -166,7 +166,7 @@ OpenStack CI environment and replicate it in your test environment.
 Using the pre-commit hook
 =========================
 
-Nova makes use of the `pre-commit framework <https://pre-commit.com/>`__ to
+Nova can make use of the `pre-commit framework <https://pre-commit.com/>`__ to
 allow running of some linters on each commit. This must be enabled locally to
 function:
 
@@ -175,6 +175,10 @@ function:
     $ pip install --user pre-commit
     $ pre-commit install --allow-missing-config
 
+As a reminder, the hooks are optional and you are not enforced to run them.
+You can either not install pre-commit or skip the hooks once by using the
+`--no-verify` flag on `git commit`.
+
 Using a remote debugger
 =======================