chore: Add named hooks for improved visibility and debugging

[kei-ichi]

This commit introduces named hooks in place of anonymous functions for the Fastify Helmet plugin. The changes include:

1. Renamed the first onRequest hook to 'helmetConfigureReply'
2. Renamed the second onRequest hook to 'helmetApplyHeaders'

These named hooks provide better visibility when inspecting routes and improve the debugging experience. This change aligns the plugin with recommendation in the Accelerate Web Development with Fastify book and other Fastify plugins like @fastify/cors that use named hooks.

The functionality remains unchanged; this is purely a developer experience improvement.

Original behavior:

---------------------------------------------------------------------------------------------------------
├── / (GET)
│   • (onRequest) ["handleCors()","anonymous()","anonymous()"]
│   • (onSend) ["addRequestIdHeaderHook()"]
│   / (HEAD)
│   • (onRequest) ["handleCors()","anonymous()","anonymous()"]
│   • (onSend) ["addRequestIdHeaderHook()","headRouteOnSendHandler()"]
└── * (OPTIONS)
    • (onRequest) ["handleCors()","anonymous()","anonymous()"]
    • (onSend) ["addRequestIdHeaderHook()"]

---------------------------------------------------------------------------------------------------------

After modified:

├── / (GET)
│   • (onRequest) ["handleCors()","helmetConfigureReply()","helmetApplyHeaders()"]
│   • (onSend) ["addRequestIdHeaderHook()"]
│   / (HEAD)
│   • (onRequest) ["handleCors()","helmetConfigureReply()","helmetApplyHeaders()"]
│   • (onSend) ["addRequestIdHeaderHook()","headRouteOnSendHandler()"]
└── * (OPTIONS)
    • (onRequest) ["handleCors()","helmetConfigureReply()","helmetApplyHeaders()"]
    • (onSend) ["addRequestIdHeaderHook()"]

Checklist

• run npm run test and npm run benchmark (benchmark command not included in package.json file)
• tests and/or benchmarks are included
• documentation is changed or added documentation is intact
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[Uzlopak]

Is there a way to write a test? Not that in few weeks somebodys comes around the corner and suggest arrow functions for less memory overhead and whatever.

@Eomm

[Eomm]

Is there a way to write a test?

I would not bother with a test, I do agree that this is a DX improvement only - no side effect on sight

[Uzlopak]

LGTM