Add links on source types to go to definition

src/librustdoc/html/render/mod.rs

@@ -30,9 +30,11 @@ mod tests;
 
 mod context;
 mod print_item;
+mod span_map;
 mod write_shared;
 
 crate use context::*;
+crate use span_map::{collect_spans_and_sources, LinkFromSrc};
 
 use std::collections::VecDeque;
 use std::default::Default;