Enum variants with multiple fields don't work.

Try applying PreciseClone in tests/expand/clone-full.rs to the following struct:

#[derive(Adhoc)]
#[derive_adhoc(PreciseClone)]
enum AllTypes {
   NoData,
   Tuple(u16, u32),
   Struct { a: String, b: String },
}

It won't work. Instead you get messages like this:

   Compiling adhoc-playground v0.1.0 (/home/nickm/src/adhoc-playground)
error: expected `,`
  --> src/main.rs:10:22
   |
10 |                       $vpat => $vtype {
   |                        ^^^^
...
21 |   #[derive(Adhoc)]
   |            ----- in this derive macro expansion
22 |   #[derive_adhoc(PreciseClone)]
23 |   enum AllTypes {
   |  ______-
24 | |     NoData,
25 | |     Tuple(u16, u32),
   | |_________- while parsing the fields for this pattern
   |
   = note: this error originates in the macro `derive_adhoc_template_PreciseClone` which comes from the expansion of the derive macro `Adhoc` (in Nightly builds, run with -Z macro-backtrace for more info)

error: expected `,`
  --> src/main.rs:26:25
   |
23 |   enum AllTypes {
   |  ______-
24 | |     NoData,
25 | |     Tuple(u16, u32),
26 | |     Struct { a: String, b: String },
   | |          -              ^
   | |__________|
   |            while parsing the fields for this pattern

(Found while writing an enums tutorial)