url: fix definitions of URL/SearchParams methods and accessors

This fixes getter and setter names for the WHATWG URL classes, and fixes
a few other inconsistencies with browsers implementations.

Co-authored-by: Gerhard Stöbich <[email protected]>

PR-URL: #36799
Reviewed-By: Antoine du Hamel <[email protected]>
Reviewed-By: Tiancheng "Timothy" Gu <[email protected]>

Author: ExE-Boss