Long awaited test case for #2355.
auto merge of #8936 : pnkfelix/rust/fsk-issue-2355-testcase, r=alexcrichton

Fix #2355.
Fix the std::fmt doc-block to show up in pandoc
auto merge of #8941 : alexcrichton/rust/fix-comment, r=thestinger
Modernized a few more types in syntax::ast