A similar change was made in the CLI itself, but is not
inherited by the code that generates the YAML docs.
Before this patch is applied;
```
usage: docker container exec [OPTIONS] CONTAINER COMMAND [ARG...] [flags]
```
With this patch applied:
```
usage: docker container exec [OPTIONS] CONTAINER COMMAND [ARG...]
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Sebastiaan van Stijn
Vincent Demeester
Daniel Nephin
Tibor Vass