Runbook Replace Incorrect Parameter

Currently the documentation on replacing the content of a runbook specifies to use the --content @/path/to/file argument. This argument will not parse correctly as it needs to be in double quotes.

The documentation should reflect this:
--content "@/path/to/file"

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#### Document Details

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* ID: cbb98a7a-2739-73ec-f20b-03367f919215
* Version Independent ID: 3125cea7-248b-9ba0-f304-248b2c766edc
* Content: [az automation runbook](https://docs.microsoft.com/en-us/cli/azure/automation/runbook?view=azure-cli-latest)
* Content Source: [latest/docs-ref-autogen/automation/runbook.yml](https://github.com/MicrosoftDocs/azure-docs-cli/blob/main/latest/docs-ref-autogen/automation/runbook.yml)
* GitHub Login: @rloutlaw
* Microsoft Alias: **routlaw**