fix: pa.dictionary and pa.schema annotation (#59)

* fix pa.dictionary annotation

* fix: schema annotation

pyarrow-stubs/__lib_pxi/types.pyi

@@ -396,6 +396,11 @@ def map_(key_type: _K, item_type: _IndexT) -> MapType[_K, _IndexT, Literal[False
 def map_(
     key_type: _K, item_type: _IndexT, key_sorted: _Ordered
 ) -> MapType[_K, _IndexT, _Ordered]: ...
+@overload
+def dictionary(
+    index_type: _IndexT, value_type: _ValueT
+) -> DictionaryType[_IndexT, _ValueT, Literal[False]]: ...
+@overload
 def dictionary(
     index_type: _IndexT, value_type: _ValueT, ordered: _Ordered
 ) -> DictionaryType[_IndexT, _ValueT, _Ordered]: ...
@@ -570,7 +575,7 @@ def ensure_type(ty: Literal["duration[ns]"]) -> DurationType[Literal["ns"]]: ...
 @overload
 def ensure_type(ty: Literal["month_day_nano_interval"]) -> MonthDayNanoIntervalType: ...
 def schema(
-    fields: Iterable[Field | tuple[str, Field]] | Mapping[str, Field],
+    fields: Iterable[Field] | Iterable[tuple[str, DataType]] | Mapping[str, DataType],
     metadata: dict[bytes, bytes] | None = None,
 ) -> Schema: ...
 def from_numpy_dtype(dtype: np.dtype) -> DataType: ...