Course ergonomics

[mre]

• What makes Rust special? -> No GC, memory safety, OOP and functional
• Add deep links to exercises (e.g. link to exercise 2/4)
• ability to copy-paste tokens from admin dashboard for team members
• store tokens in cookie
• Syntax highlighting for rustc output in Playground
• Use same snippet for Rust Playground and code boxes (code sharing)
• 35 /24 should not be a valid "progress." 😆
• A whirlwind tour of Rust: What makes Rust special? What are things you can do? Borrowing/Ownership/Traits/Pattern-Matching/Enums/Result/Option/Iterator-Patterns
• Maybe show the current subsection (the current exercise) when scrolling down on a page?
• Move Ownership topic before Option/Result