Correct title,name and synopsis in generated man pages for subcommands

[Will-Shanks]

Print the "full" command in the name,title, and synopsis of subcommand man pages. Currently if clap was to generate a man page for git add the title and name would be simply add, not git-add like expected, and the synopsis would be add <args> not git add <args>

• This PR changes this to obtain the title and name the same way as the subcommand names list in a man page, which was fixed by [clap_mangen]fix: use proper sub-command name in manpages #4255
• To obtain the proper usage string (ex: git add not git-add) I believe we want Command.usage_name, but it is private and the only way I could find to obtain it is via Command.render_usage() which unfortunately forces an unnecessary clone. This also causes duplication of positional arguments (as can be seen below with <COMMAND> (the struct name) and <subcommands> both appearing in the synopsis. Suggestions on how to fix that are appreciated. Fixed thanks to @EdJoPaTo suggestions 🎉

Some minimal code to generate a cli with multiple sub (and subsub) commands to reproduce this can be found in my fork here

Additional context can be found in #4231

example (command = mrc temp from my linked test code)
Before:

temp(1)    General Commands Manual    temp(1)

NAME
       temp

SYNOPSIS
       temp [-h|--help] <subcommands>

After:

mrc-temp(1)    General Commands Manual    mrc-temp(1)

NAME
       mrc-temp

SYNOPSIS
       mrc temp [-h|--help] <subcommands>

[EdJoPaTo]

Came across the same issue and found the PR which handles this nearly as expected. I have some thoughts to improve it (and hopefully get it merged sooner than later).

As the CI highlights (cargo test): tests/snapshots/sub_subcommand_help.roff needs an update. (Likely after the synopsis works correctly)

[Will-Shanks]

Thanks to @EdJoPaTo's suggestions all tests are now passing, I also updated the top comment with the new man page before/after.

[epage]

Thanks!