Update Rust crate mdbook to v0.4.42

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
mdbook	dependencies	patch	0.4.40 -> 0.4.42

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Release Notes

rust-lang/mdBook (mdbook)

v0.4.42

Compare Source

v0.4.41...v0.4.42

Fixed

• Fixed chapter list folding.
  #​2473

v0.4.41

Compare Source

v0.4.40...v0.4.41

Added

• Added preliminary support for Rust 2024 edition.
  #​2398
• Added a full example of the remove-emphasis preprocessor.
  #​2464

Changed

• Adjusted styling of clipboard/play icons.
  #​2421
• Updated to handlebars v6.
  #​2416
• Attr and section rules now have specific code highlighting.
  #​2448
• The sidebar is now loaded from a common file, significantly reducing the book size when there are many chapters.
  #​2414
• Updated dependencies.
  #​2470

Fixed

• Improved theme support when JavaScript is disabled.
  #​2454
• Fixed broken themes when localStorage has an invalid theme id.
  #​2463
• Adjusted the line-height of superscripts (and footnotes) to avoid adding extra space between lines.
  #​2465

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