Create flashcard decks for new concept docs

[travisjneuman]

New concept docs were added (type-hints, dataclasses, match-case, modern-tooling, reading-error-messages) but don't have matching flashcard decks in practice/flashcards/.

Create: 5 flashcard .json files following the existing format.

[travisjneuman]

Resolved in 36dceb1: Created 34 flashcard decks (274 cards total) covering all concept docs in practice/flashcards/.