Add a comment missing from 5aff0e7

For some reason, I had this comment in my local tree but not in the
branch I sent with the PR.
Remove libworkcache

This was only ever used by rustpkg and is very unmaintained.

[breaking-change]
Use RHS's struct def ID for error messages in pattern matching

Fixes #14541
auto merge of #14556 : sfackler/rust/kill-workcache, r=alexcrichton

This was only ever used by rustpkg and is very unmaintained.

[breaking-change]
Remove unnecessary allocations / clones during method lookup

By dropping the intermediate vector that holds the relevant candidates
including duplicates and directly building the vector that has the
duplicates removed we can eliminate quite a few allocations. This
reduces the times for type checking by 5-10% (measured with libstd,
libsyntax and librustc).
auto merge of #14557 : zwarich/rust/missing-comment, r=alexcrichton

For some reason, I had this comment in my local tree but not in the
branch I sent with the PR.
auto merge of #14563 : dotdash/rust/clone_kill, r=huonw

By dropping the intermediate vector that holds the relevant candidates
including duplicates and directly building the vector that has the
duplicates removed we can eliminate quite a few allocations. This
reduces the times for type checking by 5-10% (measured with libstd,
libsyntax and librustc).
Fix broken markup in query_to_str documentation
auto merge of #14565 : fhartwig/rust/master, r=sfackler
auto merge of #14562 : jakub-/rust/issue-14541, r=alexcrichton

Fixes #14541
Make the match arm type mismatch message point to the arm's span

Fixes #11319
libtest: Only colorize output if stdout is a tty

Fixes #14570.
Rename variable in tutorial

Renamed `owned_box` to `on_the_heap` to use a consistent
naming across the tutorial and the life time guide.
Also it makes the example easier to grasp.
Fix example in lifetime guide

This rewrites the example to also be more aligned with
the same example given in the main tutorial.
auto merge of #14566 : cburgdorf/rust/patch-1, r=cmr

Renamed `owned_box` to `on_the_heap` to use a consistent
naming across the tutorial and the life time guide.
Also it makes the example easier to grasp.
auto merge of #14567 : cburgdorf/rust/patch-2, r=brson

This rewrites the example to also be more aligned with
the same example given in the main tutorial.
doc: add an `.as_slice` example to the cheatsheet.

A lot of questions about this on IRC and stackoverflow.
auto merge of #14561 : jakub-/rust/issue-11319, r=alexcrichton

Fixes #11319
rustdoc: Refactor structure of html::run

Instead of one giant function, this breaks it up into several smaller functions
which have explicit dependencies among one another.

There are no code changes as a result of this commit.
rustdoc: Freeze the cache ASAP

The cache is going to be used earlier in the HTML generation process, which
means that it needs to get into TLS as soon as possible.