fix: generate help for recursive custom types

[willemneal]

Fixes #1588

Initial minimal failing example. Looking into it, the fix is that we need to change the way the help generates types and their examples. Currently it assumes that types aren't self referential, hence when generating the enum cases it keeps recursing.

So one solution is to create a types table and perhaps use a stack instead. Either way this is a bigger change than I had initially hoped.

[elizabethengelman]

Before:

$ stellar contract invoke --source ee --network local --id custom-types -- recursive_enum --help

thread 'main' (2354011) has overflowed its stack
fatal runtime error: stack overflow, aborting

After:

$ stellar contract invoke --source ee --network local --id custom-types -- recursive_enum --help

Usage Notes:
Each arg has a corresponding --<arg_name>-file-path which is a path to a file containing the corresponding JSON argument.
Note: The only types which aren't JSON are Bytes and BytesN, which are raw bytes

Usage: recursive_enum [OPTIONS]

Options:
      --recursive <List(Array<RecursiveEnum | Void>) | Void>
          Example:
            --recursive '{"List":[ {"List":[ {"List":[ RecursiveEnum ]}|"Void" ]}|"Void" ]}|"Void"'

  -h, --help
          Print help (see a summary with '-h')

[mootz12]

Leaving review as comment as I am not familiar with this code.

LG2M outside of leftover debug log.

cc @fnando

[fnando]

looks good!

[elizabethengelman]

@fnando @mootz12 I addressed the feed back y'all gave me, thanks! This should be good to go