rollup merge of #20377: alexcrichton/issue-20352

diff --cc src/libcollections/string.rs
Simple merge

diff --cc src/libcollections/vec.rs
Simple merge

diff --cc src/librustdoc/html/markdown.rs
Simple merge

diff --cc src/librustdoc/html/render.rs
Simple merge

diff --cc src/libstd/failure.rs
Simple merge

diff --cc src/libstd/io/mod.rs
Simple merge

diff --cc src/libstd/rt/unwind.rs
Simple merge

diff --cc src/libstd/rt/util.rs
Simple merge

diff --cc src/libtest/lib.rs
Simple merge