[ENHANCEMENT] Update the formatting of the help manual

[junnunkarim]

Can you update the help manual to show different sections like your website and make it so that it behaves like navigating with less?

You may refer to nnn's help manual. Here's a screenshot of it -

(Sorry for creating too many issues without providing any help from my side. I am unfamiliar with rust, so currently I am unable to help. I really loved the navigation style of felix compared to nnn, it feels so natural. Thank you for this.)

[kyoheiu]

Yes, that is one way to show the manual, which I think a lot of CLI apps implement.
But is it really necessary to read the manual in the less style, especially when there is not so much texts like in felix?
If I'm going to implement this I may need to introduce another crate, which is not always a good option, so we need to have others' opinion on this.

[junnunkarim]

@kyoheiu
On second thought, I now also think that adding a new crate might not be a good idea to view just some small amount of text.
But how about just formatting the output of the manual? Like adding sections so that it's easy to find keymaps?