doc: Remove invalid commas for hcl examples

[tsingletonacic]

Description

Documentation change, invalid commas in HCL examples for shell-local provisioner

Resolved Issues

N/A

Rollback Plan

N/A

Changes to Security Controls

N/A

[hashicorp-cla-app]

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[hashicorp-cla-app]

Thank you for your submission! We require that all contributors sign our Contributor License Agreement ("CLA") before we can accept the contribution. Read and sign the agreement

Learn more about why HashiCorp requires a CLA and what the CLA includes

_{Have you signed the CLA already but the status is still pending? Recheck it.}