prompt for argument automatically, *If* we determine an example requires arguments

[rnag]

• cargo-rx version: 0.1
• Rust Compiler (rustc) version: 1.59
• Operating System: Mac OS X

Description

I want rx to automatically prompt for arguments -- i.e. same as invoking --parse-args -- when we can determine that an example script requires arguments passed in from command-line.

Some ideas on what might work:

• Scan example file for a markdown header in doc comments, like //! # Arguments
• Look for a specific keyword in either doc comments or just regular comments. For instance, the keyword might be like rx:requires_args. This way our script knows for certain that a script requires command-line arguments, and can prompt user to input arguments automatically.