url.natvis doesn't work with Rust 1.85

[lzybkr]

I downloaded url.natvis to work around #1039.

In windbg, after running .nvload url.natvis, I found the visualizer wasn't working. After a little investigation, the issue is this line:

    <Intrinsic Name="ptr" Expression="serialization.vec.buf.ptr.pointer.pointer" />

It should be:

    <Intrinsic Name="ptr" Expression="serialization.vec.buf.inner.ptr.pointer.pointer" />

This points out an issue that might be hard to solve - the expression depends on which version of Rust you're compiling with.