fix: improve accuracy of vanity wallet function comments

[Galoretka]

Fix misleading comments in vanity wallet functions:

• Remove incorrect "nonce" reference from create_matcher function comment
• Clarify that create_nonce_matcher captures nonce in closure, not passed to returned function
• Make function descriptions more precise and accurate

The create_matcher function does not use nonce and checks wallet addresses directly,
while create_nonce_matcher uses nonce to check contract addresses created with
the specified nonce.

[Rahul-cyber26]

updates