Auto merge of #33151 - ollie27:rustdoc_abi, r=alexcrichton

rustdoc: Cleanup ABI rendering

Use a common method for rendering `extern "<abi>"`.

This now consistently shows `extern fn` rather than `extern "C" fn`.

src/librustdoc/html/render.rs

@@ -2158,8 +2158,6 @@ fn render_assoc_item(w: &mut fmt::Formatter,
               d: &clean::FnDecl,
               link: AssocItemLink)
               -> fmt::Result {
-        use syntax::abi::Abi;
-
         let name = meth.name.as_ref().unwrap();
         let anchor = format!("#{}.{}", shortty(meth), name);
         let href = match link {
@@ -2186,10 +2184,7 @@ fn render_assoc_item(w: &mut fmt::Formatter,
                    {generics}{decl}{where_clause}",
                ConstnessSpace(vis_constness),
                UnsafetySpace(unsafety),
-               match abi {
-                   Abi::Rust => String::new(),
-                   a => format!("extern {} ", a.to_string())
-               },
+               AbiSpace(abi),
                href = href,
                name = name,
                generics = *g,