docs: correct the URL example in snakeizeKeysDeep's JSDoc

[zunixport]

Summary

The JSDoc for snakeizeKeysDeep claimed URL → url. The function actually
returns u_r_l. Comment-only fix; no runtime change.

The bug

camelToSnake splits every uppercase character after position 0:

key.replace(/[A-Z]/g, (ch, i) =>
  i === 0 ? ch.toLowerCase() : `_${ch.toLowerCase()}`,
)

[ryanio]

Thanks @zunixport, you're right that URL comes out as u_r_l. This repo is a read-only mirror of our monorepo, so I recreated the fix there in ProjectOpenSea/opensea-devtools#784 (now merged) with you credited as co-author. I kept the one-word correction and dropped the extra sentence, since camelToSnake already documents the position-0 guard. The same wrong example was in the 11.0.0 CHANGELOG entry, so that's fixed too. It will ship in the next sdk release. Closing this one since mirror PRs can't be merged directly.