Fix documentation for end-to-end command

[CharlesTaylor7]

It seems like the command was renamed at some point from end2end to end-to-end.

[stappersg]

$ cargo leptos end2end
error: unrecognized subcommand 'end2end'

  tip: a similar subcommand exists: 'end-to-end'

Usage: cargo-leptos [OPTIONS] <COMMAND>

For more information, try '--help'.
$ cargo leptos help | grep end
  end-to-end  Start the server and end-2-end tests
          Output logs from dependencies (multiple --log accepted)
$

In other words: Please merge

[gbj]

Thanks very much, and apologies for the slowness on my end!