Support `"name"` / `"key"` / `"condition"` for switch statements

[pokey]

• Work started in Support "name" / "key" / "condition" for switch statements #1150
• See Add keyword for alternatives in a match construct #579 (comment) for discussion

• Typescript
• C++
• C#
• Java
• Python
• Rust

[AndreasArvidsson]

Condition is obvious, but what does name and key refer to? The argument being evaluated?
I can't get key or name to work in python even though that is checked in this issue.