Fix code snippets coloring macOS and Linux

[YorickdeJong]

Current behavior

Coloring of code snippets for macOS and Linux was not working

Proposed changes

I have added a default background of dark when the background of the terminal cannot be determined. Furthermore, a syntect to ansi function has been added for better code coloring in /ockam_command/docs.rs

Checks

• [x] All commits in this Pull Request are signed and Verified by Github.
• [x ] All commits in this Pull Request follow the Ockam commit message convention.
• [ x] There are no Merge commits in this Pull Request. Ockam repo maintains a linear commit history. We merge Pull Requests by rebasing them onto the develop branch. Rebasing to the latest develop branch and force pushing to your Pull Request branch is okay.
• [ x] I have read and accept the Ockam Community Code of Conduct.
• [x ] I have read and accepted the Ockam Contributor License Agreement by adding my Git/Github details in a row at the end of the CONTRIBUTORS.csv file in a separate pull request to the build-trust/ockam repository. The easiest way to do this is to edit the CONTRIBUTORS.csv file in the github web UI and create a separate Pull Request, this will mark the commit as verified.

[YorickdeJong]

@nazmulidris

[adrianbenavides]

Btw, you need to open a separate PR to accept the contributor's license agreement, otherwise, we won't be able to merge your PR.

I have read and accepted the Ockam Contributor License Agreement by adding my Git/Github details in a row at the end of the CONTRIBUTORS.csv file in a separate pull request to the build-trust/ockam repository. The easiest way to do this is to edit the CONTRIBUTORS.csv file in the github web UI and create a separate Pull Request, this will mark the commit as verified.

[adrianbenavides]

Looks good. We need to do some cleanup of the commits before we can proceed:

• You need to squash all commits into a single one. You have some merge commits that could cause some problems. If you need to keep your branch up to date with develop, you should run git rebase develop
• Use a valid commit message like the one from this commit
• Fix the conflicts with develop

Let me know if you need help along the way 👍

[adrianbenavides]

I've done some small modifications to the PR to make the CI checks pass, but there is an issue with termbg and we need to wait until the following PR is merged: https://github.com/dalance/termbg/pull/22

[adrianbenavides]

Will get merged through https://github.com/build-trust/ockam/pull/7731

Thanks again @YorickdeJong for your help with this one!! 🙏