2 spaces is the most common indentation width used in the docs; adjust
the rest for consistency.

Also change .editorconfig accordingly.

This reverts commit 4e070312.

The recommendation is not sufficient at this time, so revert it.

See #1898 for further discussion.

This reverts commit b92e4044.

Committing in this case is unnecessary as that job is already handled by 998-commit
which is in a superior position to commit, as it is run after all relevant changes to
the configuration have been made.