Export typings and fix minor style issue in python bindings (#1743)

Author: egparedes

.python_package/setup.cfg.in

@@ -31,6 +31,7 @@ python_requires = >=3.8
 	*.hpp
 	*.h
 	*.cmake
+	py.typed
 
 [options.packages.find]
 where = src

.python_package/src/gridtools_cpp/__init__.py

@@ -9,12 +9,12 @@
 import pathlib
 
 
-_file = pathlib.Path(__file__)
+_FILE = pathlib.Path(__file__)
 
 
 def get_cmake_dir() -> pathlib.Path:
-    return _file.parent / "data" / "lib" / "cmake" / "GridTools"
+    return _FILE.parent / "data" / "lib" / "cmake" / "GridTools"
 
 
 def get_include_dir() -> pathlib.Path:
-    return _file.parent / "data" / "include"
+    return _FILE.parent / "data" / "include"