docs/development: add section about codespell

docs/development/README.md

@@ -5,3 +5,51 @@ This is a developer docs directory. Not meant for end users.
 ## Contents
 
 - [Update component configuration.](./updating-components.md)
+
+## Spell checking
+
+As part of the CI process, we run [codespell](https://github.com/codespell-project/codespell) to find potential
+typos in our code base. This section describes how to configure and use it.
+
+### Running locally
+
+To run `codespell` locally, install it either using the [official method](https://github.com/codespell-project/codespell#installation)
+or using a package manager specific to your Linux distribution.
+
+With `codespell` installed, run the following command to run spell checking locally:
+```sh
+make codespell
+```
+
+### Ignoring specific words
+
+Sometimes, `codespell` detects some words as typos, like `AKS`, `ACI` or `IAM`, which cause the CI to
+report errors. To resolve that, we define our list of ignored words in the `.codespell.ignorewords` file,
+which is then passed to `codespell` via the `--ignore-words` flag.
+
+If you find that some word you used should be ignored, add it to this file.
+
+### Ignoring vendored files
+
+Lokomotive ships some 3rd party code like vendored Go dependencies and Helm charts, which are maintained
+by other people and may also contain some typos. It is recommended to configure `codespell` to **SKIP** those
+files from checking, instead of **FIXING** them in our repository, to avoid deriving from upstream code, which
+may make the update process of this code more difficult in the future (merge conflicts, extensive diffs etc.).
+
+To skip some file or directory (recursively) from spell checking, add the path to `.codespell.skip` file.
+The content of this file is then passed to the `--skip` flag of `codespell`.
+
+Additionally, if time allows, consider fixing the found typos in the respective upstream projects.
+
+### Spell checking git commit messages
+
+Spell checking of git commit messages is not done as part of the CI process, but it is recommended to do it locally
+before submitting patches.
+
+To check for typos in commit messages of your feature branch, you can run the following command:
+```sh
+git log master..HEAD | codespell -
+```
+
+It will spell check both commit messages and new code, so it is recommended to first fix typos in the code before
+running it, to only find typos in commit messages.