Introduce help entry and add options to smartlog

[john-h-k]

I have been using git branchless for only about 3 weeks now but I find it utterly invaluable as a tool. That being said, the lack of man pages for most commands can be a bit of a pain, and particularly the lack of options/manual on how to reduce the volume of data shown by smartlog. I would be happy to help contribute these features if there was a discussion around what would be added (I have peeked at the codebase and have a vague gist of how things work)

[arxanas]

Hi @john-h-k, thanks for your interest! The best reference for the smartlog at present would be https://github.com/arxanas/git-branchless/wiki/Command:-git-smartlog. Feel free to add a section/touch-up anything there.

Unfortunately, actually generating and installing man-pages turns out to be difficult (see https://github.com/arxanas/git-branchless/pulls?q=man-pages for my attempt). cargo itself does not have any mechanism to install man-pages; this should be provided by the system package manager. However, a plurality of users(/survey respondents) install via cargo install, so we wouldn't want to lock documentation behind a system that most users can't access.

Table of same data:

Method	Count	Percentage
cargo install	7	43.8%
Nix/NixOS	4	25%
Package manager	3	18.8%
GitHub actions	1	6.3%
From source	1	6.3%

[john-h-k]

The best reference for the smartlog at present would be https://github.com/arxanas/git-branchless/wiki/Command:-git-smartlog. Feel free to add a section/touch-up anything there.

Wonderful, thanks. I'll take a look

About the man pages, I myself don't currently know how the git internal ones work (git <cmd> --help), but I would be surprised if there wasn't a good way for extensions to do it. For me, I find that git branchless smartlog --help works but git smartlog --help doesn't which is frustrating

[arxanas]

Git is fairly inflexible on this. When I last checked the source code, I found that you can't really customize the behavior of --help. But you can customize the man viewer that's invoked, which could then figure out where to read the man pages from, which I think is what my last attempted workaround does.