Bump rand from 0.8.5 to 0.8.6 in /doc/mdbook-slosh-eval

Bumps [rand](https://github.com/rust-random/rand) from 0.8.5 to 0.8.6.
- [Release notes](https://github.com/rust-random/rand/releases)
- [Changelog](https://github.com/rust-random/rand/blob/0.8.6/CHANGELOG.md)
- [Commits](rust-random/rand@0.8.5...0.8.6)

---
updated-dependencies:
- dependency-name: rand
  dependency-version: 0.8.6
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Cargo.toml

@@ -54,7 +54,7 @@ nix = "0.29"
 chrono = "0.4.38"
 
 static_assertions = "1.1.0"
-rand = "0.8.5"
+rand = "0.8.6"
 walkdir = "2.5.0"
 same-file = "1.0.6"
 trybuild = "1.0.101"