Python: Add rm -rf dist/ step

To avoid committing the convience artifacts
to the Apache SVN, that should go to PyPi

python/mkdocs/docs/how-to-release.md

@@ -44,9 +44,10 @@ export LAST_COMMIT_ID=$(git rev-list ${GIT_TAG} 2> /dev/null | head -n 1)
 
 The `-s` option will sign the commit. If you don't have a key yet, you can find the instructions [here](http://www.apache.org/dev/openpgp.html#key-gen-generate-key). To install gpg on a M1 based Mac, a couple of additional steps are required: https://gist.github.com/phortuin/cf24b1cca3258720c71ad42977e1ba57
 
-Next step is to create a source distribution (`sdist`) which will generate a `.tar.gz` with all the source files. These files need to be uploaded to the Apache SVN.
+Next step is to clean remove the `dist/` directory to make sure that we have a clean start. Create a source distribution (`sdist`) which will generate a `.tar.gz` with all the source files using `poetry build`. These files need to be uploaded to the Apache SVN.
 
-```
+```sh
+rm -rf dist/
 poetry build
 ```
 
@@ -94,7 +95,7 @@ poetry build
 twine upload -s dist/*
 ```
 
-Finally step is to generate the email what send to the dev mail list:
+Final step is to generate the email to the dev mail list:
 
 ```bash
 cat << EOF > release-announcement-email.txt