error: type parameter goes unused in function definition
      --> tests/marker.rs:10:34
       |
    10 |             fn assert_implemented<T: $($marker +)+>() {}
       |                                  ^^^^^^^^^^^^^^^^^^
    ...
    42 | assert_impl!(Delimiter is Send and Sync);
       | ---------------------------------------- in this macro invocation
       |
       = help: consider removing the parameter
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_type_parameters
       = note: `-D clippy::extra-unused-type-parameters` implied by `-D clippy::all`
       = note: this error originates in the macro `assert_impl` (in Nightly builds, run with -Z macro-backtrace for more info)

    error: type parameter goes unused in function definition
      --> tests/marker.rs:10:34
       |
    10 |             fn assert_implemented<T: $($marker +)+>() {}
       |                                  ^^^^^^^^^^^^^^^^^^
    ...
    43 | assert_impl!(Spacing is Send and Sync);
       | -------------------------------------- in this macro invocation
       |
       = help: consider removing the parameter
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_type_parameters
       = note: this error originates in the macro `assert_impl` (in Nightly builds, run with -Z macro-backtrace for more info)

    error: type parameter goes unused in function definition
      --> tests/marker.rs:10:34
       |
    10 |               fn assert_implemented<T: $($marker +)+>() {}
       |                                    ^^^^^^^^^^^^^^^^^^
    ...
    80 | /     assert_unwind_safe! {
    81 | |         Delimiter
    82 | |         Group
    83 | |         Ident
    ...  |
    90 | |         TokenTree
    91 | |     }
       | |_____- in this macro invocation
       |
       = help: consider removing the parameter
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_type_parameters
       = note: this error originates in the macro `assert_impl` which comes from the expansion of the macro `assert_unwind_safe` (in Nightly builds, run with -Z macro-backtrace for more info)

    error: non-binding `let` without a type annotation
       --> src/fallback.rs:433:9
        |
    433 |         let _ = name;
        |         ^^^^^^^^^^^^^
        |
        = help: consider adding a type annotation or removing the `let` keyword
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_untyped
        = note: `-D clippy::let-underscore-untyped` implied by `-D clippy::pedantic`

    error: non-binding `let` without a type annotation
       --> src/fallback.rs:940:21
        |
    940 |                     let _ = write!(escaped, "\\x{:02X}", b);
        |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        |
        = help: consider adding a type annotation or removing the `let` keyword
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_untyped

    warning: unused attribute
      --> tests/test_size.rs:27:60
       |
    27 | #[cfg_attr(not(all(wrap_proc_macro, not(span_locations))), ignore)]
       |                                                            ^^^^^^
       |
       = note: #[warn(unused_attributes)] on by default

Add DelimSpan to hold the 3 different spans of a delimiter

Rename 'stable' terminology to 'fallback'