Adds deref call in assertion for hickory-client README example

[akappel]

I pasted the example code from the hickory-client README example into a brand new project. Building gave the following error message:

error[E0308]: mismatched types
  --> src/main.rs:30:25
   |
30 |         assert_eq!(*ip, Ipv4Addr::new(93, 184, 216, 34))
   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `A`, found `Ipv4Addr`
   |
help: try wrapping the expression in `hickory_client::rr::rdata::A`
   |
30 |         assert_eq!(*ip, hickory_client::rr::rdata::A(Ipv4Addr::new(93, 184, 216, 34)))
   |                         +++++++++++++++++++++++++++++                               +

For more information about this error, try `rustc --explain E0308`.

It looks like we need an extra deref *, or a call to .deref(). I opted for the latter. The code compiles as expected now. Please let me know if there is a preference for the former solution instead.

[akappel]

I also just realized that ip might be misleading, since the ref is &A. Maybe I should change the variable name to a_rdata?

[djc]

Thanks for the PR!

I think the right fix here is more like making the pattern something like Some(RData::A(A(ip))).

[akappel]

@djc - makes sense! done!