ENH: add type stubs from numpy-stubs

Add the type stubs and tests from numpy-stubs. Things this entails:

- Copy over the stubs (numpy/__init__.pyi and
  numpy/core/_internal.pyi)
  - The only modification made was removing `ndarray.tostring` since
    it is deprecated
- Update some setup.py files to include pyi files
- Move the tests from numpy-stubs/tests into numpy/tests
  - Skip them if mypy is not installed (planning on setting up CI in a
    future PR)
  - Add a mypy.ini; use it to configure mypy in the tests
    - It tells mypy where to find NumPy in the test env
    - It ignores internal NumPy type errors (since we only want to
      consider errors from the tests cases)
  - Some small edits were made to fix test cases that were emitting
    deprecation warnings
 - Add numpy/py.typed so that the types are picked up in an
   installed version of NumPy

1 files changed, 35 insertions, 0 deletions

diff --git a/numpy/tests/reveal/ndarray_shape_manipulation.py b/numpy/tests/reveal/ndarray_shape_manipulation.py
new file mode 100644
index 000000000..a44e1cfa1
--- /dev/null
+++ b/numpy/tests/reveal/ndarray_shape_manipulation.py
@@ -0,0 +1,35 @@
+import numpy as np
+
+nd = np.array([[1, 2], [3, 4]])
+
+# reshape
+reveal_type(nd.reshape())  # E: numpy.ndarray
+reveal_type(nd.reshape(4))  # E: numpy.ndarray
+reveal_type(nd.reshape(2, 2))  # E: numpy.ndarray
+reveal_type(nd.reshape((2, 2)))  # E: numpy.ndarray
+
+reveal_type(nd.reshape((2, 2), order="C"))  # E: numpy.ndarray
+reveal_type(nd.reshape(4, order="C"))  # E: numpy.ndarray
+
+# resize does not return a value
+
+# transpose
+reveal_type(nd.transpose())  # E: numpy.ndarray
+reveal_type(nd.transpose(1, 0))  # E: numpy.ndarray
+reveal_type(nd.transpose((1, 0)))  # E: numpy.ndarray
+
+# swapaxes
+reveal_type(nd.swapaxes(0, 1))  # E: numpy.ndarray
+
+# flatten
+reveal_type(nd.flatten())  # E: numpy.ndarray
+reveal_type(nd.flatten("C"))  # E: numpy.ndarray
+
+# ravel
+reveal_type(nd.ravel())  # E: numpy.ndarray
+reveal_type(nd.ravel("C"))  # E: numpy.ndarray
+
+# squeeze
+reveal_type(nd.squeeze())  # E: numpy.ndarray
+reveal_type(nd.squeeze(0))  # E: numpy.ndarray
+reveal_type(nd.squeeze((0, 2)))  # E: numpy.ndarray