Update Rust crate mdbook to ^0.4.33

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
mdbook	dependencies	patch	^0.4.32 -> ^0.4.33

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Release Notes

rust-lang/mdBook (mdbook)

### [`v0.4.33`](https://togithub.com/rust-lang/mdBook/blob/HEAD/CHANGELOG.md#mdBook-0433) [Compare Source](https://togithub.com/rust-lang/mdBook/compare/v0.4.32...v0.4.33) [v0.4.32...v0.4.33](https://togithub.com/rust-lang/mdBook/compare/v0.4.32...v0.4.33) ##### Added - The `color-scheme` CSS property is now set based on the light/dark theme, which applies some slight color differences in browser elements like scroll bars on some browsers. [#​2134](https://togithub.com/rust-lang/mdBook/pull/2134) ##### Fixed - Fixed watching of extra-watch-dirs when not running in the book root directory. [#​2146](https://togithub.com/rust-lang/mdBook/pull/2146) - Reverted the dependency update to the `toml` crate (again!). This was an unintentional breaking change in 0.4.32. [#​2021](https://togithub.com/rust-lang/mdBook/pull/2021) - Changed macOS change notifications to use the kqueue implementation which should fix some issues with repeated rebuilds when a file changed. [#​2152](https://togithub.com/rust-lang/mdBook/pull/2152) - Don't set a background color in the print page for code blocks in a header. [#​2150](https://togithub.com/rust-lang/mdBook/pull/2150)

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