Add future annotations imports

Author: JamesParrott

src/shapefile/_doctest_runner.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import doctest
 import sys
 from collections.abc import Iterable, Iterator

src/shapefile/constants.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import os
 
 # Module settings

src/shapefile/geometric_calculations.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from collections.abc import Iterable, Iterator, Reversible
 
 from .exceptions import RingSamplingError

src/shapefile/helpers.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import array
 import os
 from os import PathLike

src/shapefile/types.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import io
 from datetime import date
 from os import PathLike