added the `--man` subcommand

[mkatychev]

• I found it easier to print the :help drawing to a stdout/vim buffer when learning the keybindings
• having a dedicated cheatsheet was easier than constantly typing :help and panning around (zoom multiplier was around than 2.0)
• apologies for naive implementation I am not familiar with the Parser object, there's likely a better way to implement this
• added :h shorthand alias (same as vim)

[mkatychev]

I have 4 failing test cases:

failures:

---- autocomplete::test::test_autocomplete_file stdout ----
thread 'autocomplete::test::test_autocomplete_file' panicked at 'assertion failed: `(left == right)`
  left: `Some(("five.png", 7..14))`,
 right: `Some(("four.png", 7..14))`', src/autocomplete.rs:242:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

---- cmd::test::test_command_line_change_dir stdout ----
thread 'cmd::test::test_command_line_change_dir' panicked at 'assertion failed: `(left == right)`
  left: `":e four.png"`,
 right: `":e five.png"`', src/cmd.rs:1188:9

---- cmd::test::test_command_line_cd stdout ----
thread 'cmd::test::test_command_line_cd' panicked at 'assertion failed: `(left == right)`
  left: `":cd assets/1"`,
 right: `":cd assets/2"`', src/cmd.rs:1209:9

---- cmd::test::test_command_line stdout ----
thread 'cmd::test::test_command_line' panicked at 'assertion failed: `(left == right)`
  left: `":e assets/four.png"`,
 right: `":e assets/five.png"`', src/cmd.rs:1123:9


failures:
    autocomplete::test::test_autocomplete_file
    cmd::test::test_command_line
    cmd::test::test_command_line_cd
    cmd::test::test_command_line_change_dir

test result: FAILED. 22 passed; 4 failed; 0 ignored; 0 measured; 0 filtered out

Checked master HEAD and those same 4 are failing, 🤷.

[cloudhead]

Thanks for this! It's a good idea, I will give it a review as soon as I have time.

I have 4 failing test cases:

That's weird, but looks like CI is passing, so it must be something on your end :thinking: .