syntax_data: {"ast_node_type":"other","tokens":[{"end":49,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     ///   we can have a single `+target` feature.
context_before:     ///   compiler, and we don't need to multiply the number of flavors for this use-case. Instead,
context_after:     /// - umbrella features: for example if clang accumulates more features in the future than just