Add crystal tool method_types for listing method parameter types

[nobodywasishere]

Feature Request

This tool would output for every method with untyped parameters, the inferred type. For example:

def my_method(param)
 param.to_s
end

my_method(1)

$ crystal tool method_types file.cr

file.cr:1:1 - ::my_method
  - param : Int32
  - return : String

This would then allow people to write code without types at first, and then later on be able to fill them in. This could also be integrated into the vscode extension to allow viewing the inferred inline type (similar to other languages like Rust). Ideally, this would also have JSON output as well.

[yxhuvud]

Would also be nice to be able to give it a line number, then it can be invoked manually on a specific method.

[straight-shoota]

Prior art: oprypin/crystal@argtohtml...annotator~#diff-bc28f7dec1
This was used for #10575

[crimson-knight]

@yxhuvud what would be the point of giving it a line number for it to tell you the type?

[yxhuvud]

@crimson-knight Then you can have a button in your editor to add it to a specific line.