feat: add options for controlling formatting

[morgante]

Introduces a custom_help_markdown which can be customized with options, while preserving backwards compatibility.

For my use case, two options were desired:

• Overriding the title
• Removing the bottom footer

[janstarke]

There has been no change to this repository since 2 years, but I was in need for a specific feature. So I forked this repo and incorporated your PR (https://github.com/janstarke/clap-markdown-dfir). I also published the release to https://crates.io. Until now I did not mention you in the Cargo.toml. I invited to as collaborator, so you can add your preferred contact data to the project, if you want to.

Kind regards, Jan

[ConnorGray]

@morgante @janstarke My sincerest apologies for the radio silence on merging the PRs that have built up in this repository. I originally wrote this tool at a time I was working on several CLI tools in Rust, but my focus changed and I was working much less actively in Rust.

I'm working through the backlog of PRs and will try to get all of them merged and new version of clap-markdown published soon.

If you have any other issues or PRs, I promise I'll do my best to merge them in a timely manner!

[ConnorGray]

I'm closing this PR as I've now integrated these changes in #25 👷

Thank you again for the contributions, and again my apologies for the delay in getting these integrated!