doc/guide-ffi: A few minor typo/language fixes

Signed-off-by: Anton Lofgren <alofgren@op5.com>
Guide: looping
Guide: Standard input
Convert a first batch of diagnostics to have error codes
auto merge of #15531 : steveklabnik/rust/guide_looping, r=brson
auto merge of #15534 : steveklabnik/rust/guide_stdin, r=brson
Extend --pretty flowgraph=ID to include dataflow results in output.

Use one or more of the following `-Z` flag options to tell the
graphviz renderer to include the corresponding dataflow sets (after
the iterative constraint propagation reaches a fixed-point solution):

  * `-Z flowgraph-print-loans` : loans computed via middle::borrowck
  * `-Z flowgraph-print-moves` : moves computed via middle::borrowck::move_data
  * `-Z flowgraph-print-assigns` : assignments, via middle::borrowck::move_data
  * `-Z flowgraph-print-all` : all of the available sets are included.

Fix #15016.

----

This also adds a module, `syntax::ast_map::blocks`, that captures a
common abstraction shared amongst code blocks and procedure-like
things.  As part of this, moved `ast_map.rs` to subdir
`ast_map/mod.rs`, to follow our directory layout conventions.

(incorporated review feedback from huon, acrichto.)
auto merge of #15371 : pnkfelix/rust/fsk-render-dataflow-on-dot, r=alexcrichton

Use one or more of the following `-Z` flag options to tell the
graphviz renderer to include the corresponding dataflow sets (after
the iterative constraint propagation reaches a fixed-point solution):

  * `-Z flowgraph-print-loans` : loans computed via middle::borrowck
  * `-Z flowgraph-print-moves` : moves computed via middle::borrowck::move_data
  * `-Z flowgraph-print-assigns` : assignments, via middle::borrowck::move_data
  * `-Z flowgraph-print-all` : all of the available sets are included.

Fix #15016.
Add low level support for polling with librustuv.

 * Adds functions for using arbitrary sockets with libuv
 * Adds types and functions required to support this.
auto merge of #15421 : catharsis/rust/doc-ffi-minor-fixes, r=alexcrichton

Signed-off-by: Anton Lofgren <alofgren@op5.com>
auto merge of #15604 : mrmonday/rust/raw-socket-libc, r=alexcrichton

This pull request adds some necessary function definitions and types for doing low level networking with Rust.
Deprecate `str::from_utf8_owned`

Use `String::from_utf8` instead

[breaking-change]
Deprecate `str::from_chars`

Use `String::from_chars` instead

[breaking-change]
Deprecate `str::from_char`

Use `String::from_char` or `.to_str` instead

[breaking-change]
Deprecate str::from_byte

Replaced by `String::from_byte`

[breaking-change]
Deprecate `str::from_utf16`

Use `String::from_utf16` instead

[breaking-change]
Deprecate `str::from_utf16_lossy`

Use `String::from_utf16_lossy` instead.

[breaking-change]
Deprecate `str::from_utf8_lossy`

Use `String::from_utf8_lossy` instead

[breaking-change]
Fix errors
auto merge of #15426 : aochagavia/rust/str, r=alexcrichton

* Deprecated `str::from_utf8_owned` in favor of `String::from_utf8`
* Deprecated `str::from_utf8_lossy` in favor of `String::from_utf8_lossy`
* Deprecated `str::from_utf16` in favor of `String::from_utf16`
* Deprecated `str::from_utf16_lossy` in favor of `String::from_utf16_lossy`
* Deprecated `str::from_chars` in favor of `String::from_chars`
* Deprecated `str::from_char` in favor of `String::from_char` and `.to_string()`
* Deprecated `str::from_byte` in favor of `String::from_byte`

[breaking-change]