Unrolled build for rust-lang#132793

Rollup merge of rust-lang#132793 - ehuss:update-mdbook, r=Mark-Simulacrum

Update mdbook to 0.4.42

This updates mdbook to 0.4.42
Changelog: https://github.com/rust-lang/mdBook/blob/master/CHANGELOG.md#mdbook-0441

There were some significant changes that I would like to get early testing on.

This also updates rust-by-example which was required due to an update to the theme file.

src/tools/rustbook/.gitignore

@@ -0,0 +1 @@
+/target

src/tools/rustbook/Cargo.lock

@@ -441,11 +441,12 @@ dependencies = [
 
 [[package]]
 name = "handlebars"
-version = "5.1.2"
+version = "6.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d08485b96a0e6393e9e4d1b8d48cf74ad6c063cd905eb33f42c1ce3f0377539b"
+checksum = "fd4ccde012831f9a071a637b0d4e31df31c0f6c525784b35ae76a9ac6bc1e315"
 dependencies = [
  "log",
+ "num-order",
  "pest",
  "pest_derive",
  "serde",
@@ -645,9 +646,9 @@ dependencies = [
 
 [[package]]
 name = "mdbook"
-version = "0.4.40"
+version = "0.4.42"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b45a38e19bd200220ef07c892b0157ad3d2365e5b5a267ca01ad12182491eea5"
+checksum = "7624879735513024d323e7267a0b3a7176aceb0db537939beb4ee31d9e8945e3"
 dependencies = [
  "ammonia",
  "anyhow",
@@ -762,6 +763,21 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "num-modular"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "17bb261bf36fa7d83f4c294f834e91256769097b3cb505d44831e0a179ac647f"
+
+[[package]]
+name = "num-order"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "537b596b97c40fcf8056d153049eb22f481c17ebce72a513ec9286e4986d1bb6"
+dependencies = [
+ "num-modular",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.19"