improve rspc integration

[oscartbeaumont]

This does some improvement to the rspc integration.

Changes:

• Depend on specta::Type not rspc::Type as rspc::Type is a reexport. This would allow your library to be used with any other Specta related library easily.

[oscartbeaumont]

As a heads up this changed is inspired by the compiler output.

➜ cargo check --all --all-features
warning: `&` without an explicit lifetime name cannot be used here
  --> src/parser.rs:26:38
   |
26 |     pub const REST_FILE_EXTENSIONS: [&str; 2] = ["http", "rest"];
   |                                      ^
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #115010 <https://github.com/rust-lang/rust/issues/115010>
   = note: `#[warn(elided_lifetimes_in_associated_constant)]` on by default
help: use the `'static` lifetime
   |
26 |     pub const REST_FILE_EXTENSIONS: [&'static str; 2] = ["http", "rest"];
   |