chore: add verbatim_doc_comment in ExecCmd::inputs_path

[lima-limon-inc]

Clap ignores the newlines from ExecCMD::input_paths's doc-comment. This hinders the comments' readability.

This PR adds the #[clap(verbatim_doc_comment)] in order for it to follow the formatting.

For reference, here's the before and after:
Before:

$~ miden-client exec --help
Execute the specified program against the specified account
(...)

  -i, --inputs-path <INPUTS_PATH>
          Path to the inputs file. This file will be used as inputs to the VM's advice map.
          
          The file should contain a TOML array of inline tables, where each table has two fields: - `key`: a 256-bit hexadecimal string representing a word to be used as a key for the input entry. The hexadecimal value must be prefixed with 0x. - `values`: an array of 64-bit unsigned integers representing field elements to be used as values for the input entry. Each integer must be written as a separate string, within double quotes.
          
          The input file should contain a TOML table called `inputs`, as in the following example: inputs = [ { key = "0x0000001000000000000000000000000000000000000000000000000000000000", values = ["13", "9"]}, { key = "0x0000000000000000000000000000000000000000000000000000000000000000" , values = ["1", "2"]}, ]

(...)

After:

(...)
  -i, --inputs-path <INPUTS_PATH>
          Path to the inputs file. This file will be used as inputs to the VM's advice map.
          
          The file should contain a TOML array of inline tables, where each table has two fields:
          - `key`: a 256-bit hexadecimal string representing a word to be used as a key for the input
            entry. The hexadecimal value must be prefixed with 0x.
          - `values`: an array of 64-bit unsigned integers representing field elements to be used as
            values for the input entry. Each integer must be written as a separate string, within
            double quotes.
          
          The input file should contain a TOML table called `inputs`, as in the following example:
             inputs = [
                 { key = "0x0000001000000000000000000000000000000000000000000000000000000000", values = ["13", "9"]},
                 { key = "0x0000000000000000000000000000000000000000000000000000000000000000" , values = ["1", "2"]},
             ]
(...)