Previously it could not be implemented for types outside `libcore/iter.rs` due
to coherence issues.

Correct mistyped comma, and slightly improve sentence.

r? @steveklabnik

Fixes #24080.

As requested by @kballard in #23844

Really minor nitpick but if you're gonna align them, they should be aligned properly.

r? @steveklabnik 

doc copy error
r? @steveklabnik

Correct mistyped comma, and slightly improve sentence.

This fixes up the "make check" part of the rust build os that the Bitrig buildbot will succeed.

Per [RFC #0505](https://github.com/rust-lang/rfcs/blob/master/text/0505-api-comment-conventions.md#formatting).

If a result is highlighted, when the search changes that state should no
longer be highlighted. Fixes #24044

cc @steveklabnik

Ran across this one while learning from the Book.

doc copy error
r? @steveklabnik

I ran across a comma splice.

I didn't set the "note:" off inside parenthesis.  I looked around in other places and saw it both ways, but without surrounding parenthesis seemed to be the more common convention followed elsewhere in the docs.  Let me know if you have an overriding preference about that and I'll change it.

r? @steveklabnik

Per [RFC #0505](https://github.com/rust-lang/rfcs/blob/master/text/0505-api-comment-conventions.md#formatting).

This syncs the _Crates and Modules_ chapter of the book with current output:

* the runs are supposed to be in the project’s directory,
* `rustc` has slightly different error messages (and things like macro line:col numbers),
* Cargo now compiles things into `target/debug`.

If a result is highlighted, when the search changes that state should no
longer be highlighted. Fixes #24044

cc @steveklabnik

 Default is now beta, add nightly in the unstable section

 Also: the std_misc feature flag is removed; it's not needed in Beta.

Hat tip to @tshepang in #23871

Fixes #24023

This PR replaces #24024

 from https://news.ycombinator.com/item?id=9317822

 This was brought up in IRC by a confused reader.

r? steveklabnik

 Kinda hoped I'd spot something else for this PR, but then didn't.

 r? @alexcrichton @brson

 Until I can figure out the correct way to configure jemalloc for Bitrig, this patch will correctly disable it.  All other build targets remain unchanged.

 Won't make it for beta, but it's rust-packaging that matters.

r? @alexcrichton

 Validate if the description is available in the rawSearchIndex

 This was supposed to be a part of #23930

 MacOS X does not ship with Java installed by default. Instead it
includes binary stubs that upon execution pop up a message suggesting
the installation of the JDK.

Since `javac` is only used when `antlr4` is available, it is possible
to work around the popup by only probing for `javac` if `antlr4` has
been successfully detected (in which case the JDK is probably already
installed on the system).

Fixes #23138.

 The existing impl had the too-strong requirement of `Clone`, when only
`ToOwned` was needed.