✨ Add support for not needing ... as default value in required Query(), Path(), Header(), etc. (#4906)

* ✨ Do not require default value in Query(), Path(), Header(), etc

* 📝 Update source examples for docs with default and required values

* ✅ Update tests with new default values and not required Ellipsis

* 📝 Update docs for Query params and update info about default value, required, Ellipsis

tests/test_multi_query_errors.py

@@ -7,7 +7,7 @@ app = FastAPI()
 
 
 @app.get("/items/")
-def read_items(q: List[int] = Query(None)):
+def read_items(q: List[int] = Query(default=None)):
     return {"q": q}