Cleanup lifetime guide
Clean pointers guide
get over bold text madness, changes per PR, brought the "returning pointers" section back to pointers guide
fix mostly grammar per PR comments
std: Remove String::from_owned_str as it's redundant

[breaking-change]
rustc: Use rust strings for failure arguments

This avoids having to perform conversions from `*u8` to `&'static str` which can
suck in a good deal of code.

Closes #14442
Use clang++ for CXX when --enable-clang.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
std: change select! docs from 'ports' to 'receivers'
fix MIPS target
serialize: Remove old commented out code
collections: add Show impl test for HashMap
collections: implement Show for Tree{Map,Set}
std: Remove String's to_owned
Fixed deprecation warning text for mem::move_val_init and its associated comment.
std: Rename strbuf operations to string

[breaking-change]
doc: Fix link to string

This was missed in 553074506ecd139eb961fb91eb33ad9fd0183acb
rust manual: supertraits seperator is wrong
rustc: clarify warning about native deps for a staticlib.

This adjusts the "unlinked native library" warning one receives when
compiling with `crate_type="staticlib"`. The warning is just trying to
tell the user that they need to link against these libraries, but the
old text wasn't making this obvious; the new text says this explicitly.
auto merge of #14447 : erickt/rust/show-treemap, r=kballard

This is a hodge podge of a couple small cleanup commits. It implements `Show` for `TreeMap` and `TreeSet`, and some removal of commented out code.
mk: Don't build any docs with --disable-docs.
auto merge of #14414 : richo/rust/features/nerf_unused_string_fns, r=alexcrichton

This should block on #14323