docs: fix parameter name in req.acceptsLanguages JSDoc

[hxperl]

The JSDoc for req.acceptsLanguages names the parameter ...lang, but the function declares ...languages, so the documented name does not exist in the signature.

Evidence (lib/request.js at HEAD, and test run after the fix):

* @param {String} ...lang
* @return {String|Array}
* @public
*/
req.acceptsLanguages = function(...languages) {

1260 passing (2s)      # npm test
exit 0                 # npx eslint lib/

Changed @param {String} ...lang to @param {String} ...languages; no code was changed.

This change was made with AI coding assistance.