Support plan

• which support plan is this issue covered by? (e.g. Community, Core, Plus, or Enterprise):
  Community
• is this issue currently blocking your project? (yes/no):
  no
• is this issue affecting a production system? (yes/no):
  yes

Context

• node version: any
• module version: 17.1.1
• environment (e.g. node, browser, native): node
• used with (e.g. hapi application, another framework, standalone, ...):
  standalone
• any other relevant information:

What problem are you trying to solve?

While I can just solve this with a regex, it would be much cleaner if this was part of the Joi API.
JavaScript's parseInt already natively handles the 0x prefix.

const somePrefixedHexString = '0x123'; 
Joi.string().hex().validate(somePrefixedHexString); // error

Do you have a new or modified API suggestion to solve the problem?

It would be amazing if I didn't have to store that regular-expression somewhere and I instead could do the following:

const somePrefixedHexString = '0x123'
Joi.string().hex({ prefix: true }).validate(somePrefixedHexString); // passes validation