Macro oatie::doc_span

macro_rules! doc_span {
    ( @str_literal $e:expr ) => { ... };
    ( @kind DocChars $b:expr $(,)* ) => { ... };
    ( @kind DocGroup { $( $e:tt : $b:expr ),+  $(,)* } , [ $( $v:tt )* ] $(,)* ) => { ... };
    ( ) => { ... };
    ( $( $i:ident ( $( $b:tt )+ ) ),+ $(,)* ) => { ... };
}