Fix syntax highlighting in code blocks

[toastal]

While other forges may support sh-session for syntax highlighting GitHub is not one of those forges. To get the expected highlighting you need a) console as the syntax and b) some sigil to start the line to indicated that it’s console input and not output. This commit normalizes these code blocks. Additionally, seeing the problems folks on zsh seem to have with the #, it’s better to string escape the that part of the shell so it’s compatible with bash, dash, fish, and zsh.

Also, one Nix block was missing a nix highlight.

To see a rendered preview of the Markdown on Microsoft GitHub, you can visit the branch's README: https://github.com/ArdanaLabs/Ardana-dApps/blob/readme-syntax/README.md

Closes

other changes

• [ ] Every newly introduced function needs to have a documentation
• [ ] The impure tests via nix run .#offchain:test were run and all are passing.
• [ ] Where applicable, grammar, punctuation, and spelling within code and comments should be plausibly correct.
• [ ] The issue(s) that the work is addressing should be linked in the PR description.
• [ ] Any significant changes beyond what's clear from the linked issue(s) are documented in the PR description