fastapi

ca437cdf - 📝 Add docs recommending `Union` over `Optional` and migrate source examples (#4908)

📝 Add docs recommending `Union` over `Optional` and migrate source examples (#4908) * 📝 Add docs recommending Union over Optional * 📝 Update docs recommending Union over Optional * 📝 Update source examples for docs, recommend Union over Optional * 📝 Update highlighted lines with updated source examples * 📝 Update highlighted lines in Markdown with recent code changes * 📝 Update docs, use Union instead of Optional * ♻️ Update source examples to recommend Union over Optional * 🎨 Update highlighted code in Markdown after moving from Optional to Union