Method `generateCsrf` return type should be a `string` instead of `FastifyReply`

Prerequisites

[X] I have written a descriptive issue title
[X] I have searched existing issues to ensure the bug has not already been reported

Fastify version

4.13.0

Plugin version

6.1.0

Node.js version

18.14.2

Operating system

Linux

Operating system version (i.e. 20.04, 11.3, 10)

Ubuntu 22.04.2 LTS

Description

The return type of the decorated generateCsrf method is FastifyReply: https://github.com/fastify/csrf-protection/blob/a48195429b0cf6fd7b233a096d35810338cc90bc/types/index.d.ts#L17-L19

Looking at the code, the generateCsrf methods return tokens.create() which is a string.

Not a big issue as the token is almost always returned or used in reply.send(), but it would be nice to have the type fixed.

Steps to Reproduce

Example:

const fastify = require('fastify')();

fastify.register(require('@fastify/cookie'));
fastify.register(require('@fastify/csrf-protection'));

fastify.get('/', (_, reply) => {
  const token = reply.generateCsrf();
  const type = typeof token;
  console.log('token type:', type); // type is 'string'
  return { token, type };
});

fastify.listen().then(address => {
  console.log('listening on', address);
});

The value of typeof token is string but the token type (hovering in VSCode) is FastifyReply.

Expected Behavior

Return type of generateCsrf method should be a string instead of FastifyReply.

fastify / csrf-protection

Method `generateCsrf` return type should be a `string` instead of `FastifyReply` #124