Macro pretty_ast_intersperse 

macro_rules! pretty_ast_intersperse {
    ($printer: expr, $docs:expr, $sep: expr$(,)?) => { ... };
}

Convert a collection of values into documents separated by another document.

It forwards to PrettyAstExt::intersperse after materialising the separator. The macro exists so call sites can stay concise while still benefiting from the allocator captured by install_pretty_helpers!.