rustdoc: Don't strip empty modules with documentation

Closes #11443
doc: build the docs for librustuv

Closes #11444
rustdoc: Get --version working

Closes #11421
rustdoc: Don't show private modules
rustc: Fix formatting of env! error message

Death to caps.
syntax: Fix capitalization in macro_parser errors
librustc: Check restrictions on all subcomponents of a path when moving
it. r=nikomatsakis
Re-implement --help in rustpkg

Fixes #11423
Fix `rustpkg help` handling

In general, you could run "rustpkg help <cmd>" to see some specific
usage information for <cmd>.  However, this was handled in a very ad-hoc
and buggy manner.  For example, running "rustpkg help prefer" would
actually show you the usage information for the "uninstall" cmd.

This commit attempts to fix this by making Help a real Command, and
making the handing of it explicit.
extra::workcache: Remove unused Logger
auto merge of #11465 : pcwalton/rust/borrow-check-bug, r=pcwalton

it. r=nikomatsakis
define arch for iOS/ARM
auto merge of #11466 : eminence/rust/fix_rustpkg_help, r=brson

It appears --help got lost in aa50ebd03ed1d1f698d0d275f9570ef53e720831

Fixes #11423
rustdoc: Don't show a fields header if there are none
auto merge of #11461 : alexcrichton/rust/rustdoc-fixes, r=brson

See the commits.
auto merge of #11468 : klutzy/rust/workcache-cleanup, r=alexcrichton
auto merge of #11463 : brson/rust/envcaps, r=huonw

Death to caps.
Removed obsolete 'e' prefix on ty_evec and ty_estr.
Removed free_glue from tydesc (the code is still generated, but inlined in drop_glue).
Use the right type for self in methods and remove obsoleted items.
Fixes #7411, #10615.