feat: update help message and usage information for asyncapi new file -h

[GauravSaini01]

Related issue(s)
Resolves #1624

Description

• Updated the help message for the asyncapi new file -h command.
  
• Modified the usage.md file to reflect the correct command syntax and example.

@derberg please review this PR

[changeset-bot]

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[asyncapi-bot]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[AayushSaini101]

LGTM