salted plaintext format or generic format tracer for debugging

There is plaintext format ($0$) that prints arguments of set_key() with --verbosity=6. I think a salted variant would be helpful to understand single mode better. I guess set_salt() and maybe crypt_all() should be reported too.

Additionally I think it would be nice to print fork's id for the call as in status line with --fork= option. Same applies to current plaintext format.

Maybe output of candidates should be quoted to allow accurate capturing of candidates by scripts.

Maybe a separate format is a wrong way. It may be better to implement generic way to trace calls at the interface of any format. This way it would be easier to replicate environment implied by certain format. An option to skip real crypt_all() may be added for speed.

Start by examining the existing plaintext format ($0$) and the interface calls named in the issue: set_key(), set_salt(), and crypt_all(), including their --verbosity=6 output. Compare this with the fork ID shown by --fork= and candidate output handling. Done should mean a decided scope for generic tracing or a salted format, with the requested fork, quoting, and optional crypt_all() behavior addressed.