Added some documentation text to sync command

[pat-earl]

Please check below, if the PR fulfills these requirements:

• [x] Commit(s) and code follow the repositories guidelines.
• [ ] Test(s) have been added or updated to support these change(s).
• [ ] Doc(s) have been added or updated to support these change(s).

Associated Links:

• N/A

Types of Changes:

• Added some documentation to the sync subcommand usage text. Clarified it's usage for local Hauler manifests.
• Included an example of using the files flag similar to products flag.

Proposed Changes:

• Provide clarifying language to the help text for the sync subcommand. I missed the --files flag my first time through the online Documentation and wanted to see it in the help text for the command.

Verification/Testing of Changes:

• Run hauler store sync --help to see the changes

Additional Context:

• This is a small change to the usage text of a CLI subcommand.