Auto merge of #67964 - JohnTitor:rollup-pu5kosl, r=JohnTitor

Rollup of 13 pull requests

Successful merges:

 - #67566 (Add an unstable conversion from thread ID to u64)
 - #67671 (Account for `type X = impl Trait;` in lifetime suggestion)
 - #67727 (Stabilise vec::remove_item)
 - #67877 (Omit underscore constants from rustdoc)
 - #67880 (Handle multiple error fix suggestions carefuly)
 - #67898 (Improve hygiene of `newtype_index`)
 - #67908 (rustdoc: HTML escape const values)
 - #67909 (Fix ICE in const pretty printing and resolve FIXME)
 - #67929 (Formatting an example for method Vec.retain)
 - #67934 (Clean up E0178 explanation)
 - #67936 (fire "non_camel_case_types" for associated types)
 - #67943 (Missing module std in example.)
 - #67962 (Update books)

Failed merges:

r? @ghost

Author: bors

src/doc/book

@@ -11,7 +11,6 @@
 #![feature(associated_type_bounds)]
 #![feature(binary_heap_into_iter_sorted)]
 #![feature(binary_heap_drain_sorted)]
-#![feature(vec_remove_item)]
 
 use std::collections::hash_map::DefaultHasher;
 use std::hash::{Hash, Hasher};

src/doc/edition-guide

@@ -1054,7 +1054,7 @@ impl<T> Vec<T> {
     ///
     /// ```
     /// let mut vec = vec![1, 2, 3, 4];
-    /// vec.retain(|&x| x%2 == 0);
+    /// vec.retain(|&x| x % 2 == 0);
     /// assert_eq!(vec, [2, 4]);
     /// ```
     ///
@@ -1696,14 +1696,13 @@ impl<T> Vec<T> {
     /// # Examples
     ///
     /// ```
-    /// # #![feature(vec_remove_item)]
     /// let mut vec = vec![1, 2, 3, 1];
     ///
     /// vec.remove_item(&1);
     ///
     /// assert_eq!(vec, vec![2, 3, 1]);
     /// ```
-    #[unstable(feature = "vec_remove_item", reason = "recently added", issue = "40062")]
+    #[stable(feature = "vec_remove_item", since = "1.42.0")]
     pub fn remove_item<V>(&mut self, item: &V) -> Option<T>
     where
         T: PartialEq<V>,

src/doc/embedded-book

@@ -2,7 +2,7 @@
 
 use crate::dep_graph::DepNode;
 use crate::ich::Fingerprint;
-use rustc_index::vec::{Idx, IndexVec};
+use rustc_index::vec::IndexVec;
 
 rustc_index::newtype_index! {
     pub struct SerializedDepNodeIndex { .. }

src/doc/nomicon

@@ -50,7 +50,6 @@
 #![feature(thread_local)]
 #![feature(trace_macros)]
 #![feature(trusted_len)]
-#![feature(vec_remove_item)]
 #![feature(stmt_expr_attributes)]
 #![feature(integer_atomics)]
 #![feature(test)]