These overloads were needed to allow passing `fs::path` objects directly to
libstdc++'s `fstream` constructors, but after the previous commit, there is no
longer any remaining code that does pass `fs::path` objects to `fstream`
constructors. Writing new code which does this is also discouraged because the
standard has been updated in https://wg21.link/lwg3430 to disallow it.
Dropping these also means its no longer possible to pass `fs::path` arguments
directly to `fstream::open` in libstdc++, which is somewhat unfortunate but not
a big loss because it is already not possible to pass them to the constructor.
So this commit updates `fstream::open` calls.
Additionally, this change required updates to src/bitcoin.cpp since it was
relying on the overloaded filename() method.
Try to make extra commands more obvious based on a suggestion from Sjors:
https://github.com/bitcoin/bitcoin/pull/31679#issuecomment-2922787970i
When `bitcoin` is invoked with no arguments, still show short help output, but
now explicitly state that more commands are available and `bitcoin help` will
list them.
Also:
- Get rid of -a/--all option. Just show all commands when `bitcoin help` or
`bitcoin --help` is used. It maybe a helpful to add an option like this if
more commands are added in the future, but right now there are not very many.
- Just show name of executable, not full path of executable in help output. This
can be a little easier to read if the path is long.
Intended to make bitcoin command line features more discoverable and allow
installing new multiprocess binaries in libexec/ instead of bin/ so they don't
cause confusion.
Idea and implementation of this were discussed in
https://github.com/bitcoin/bitcoin/issues/30983
Co-authored-by: Sjors Provoost <sjors@sprovoost.nl>
