Add --show to select command

[mtdowling]

--show is used to include additional data in select command output, including the shape type, file where the shape is defined, and/or variables captured when the shape was matched.

For example:

smithy select --selector 'structure $neighbors(>)' --show-traits documentation --show type,file,vars --aut s3.json

Outputs:

[
    {
        "shape": "com.amazonaws.s3#CSVInput",
        "type": "structure",
        "file": "/path/to/s3.json:16224:34",
        "vars": {
            "neighbors": [
                "com.amazonaws.s3#CSVInput$AllowQuotedRecordDelimiter",
                "com.amazonaws.s3#CSVInput$Comments",
                "com.amazonaws.s3#CSVInput$FieldDelimiter",
                "com.amazonaws.s3#CSVInput$FileHeaderInfo",
                "com.amazonaws.s3#CSVInput$QuoteCharacter",
                "com.amazonaws.s3#CSVInput$QuoteEscapeCharacter",
                "com.amazonaws.s3#CSVInput$RecordDelimiter"
            ]
        },
        "traits": {
            "smithy.api#documentation": "<p>Describes how an uncompressed comma-separated values (CSV)-formatted input object is formatted.</p>"
        }
    }
]

This now deprecates the --show-vars option, as --show vars should be used instead.

Issue #, if available:

Description of changes:

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