docs: Fix inconsistencies in documentation (#2190)

This PR fixes some typos and formatting artifacts in the documentation
files.

It also removes the `version: ` field from the Docker Compose setup
instruction, as it is
[obsolete](https://docs.docker.com/reference/compose-file/version-and-name/#version-top-level-element-obsolete).

> Compose always uses the most recent schema to validate the Compose
file, regardless of the version field.

Note: I also noticed the version field in the `docker-compose.yml`
files, but was unsure whether removing it would affect backward
compatibility.