✨ 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

docs_src/header_params/tutorial002_py310.py

@@ -5,6 +5,6 @@ app = FastAPI()
 
 @app.get("/items/")
 async def read_items(
-    strange_header: str | None = Header(None, convert_underscores=False)
+    strange_header: str | None = Header(default=None, convert_underscores=False)
 ):
     return {"strange_header": strange_header}