fixed reading 10x formatted visium mtx files (#803)

* fixed reading 10x formatted visium mtx files

solves #802

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update notes-dev.rst

added release notes

* Update _utils.py

fixed counts file suffix to match 10x spec

* Update docs/release/notes-dev.rst

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Giovanni Palla <25887487+giovp@users.noreply.github.com>

docs/release/notes-dev.rst

@@ -1,2 +1,4 @@
 Squidpy dev (the-future)
 ========================
+- Fixed the reading of 10x formatted mtx files `@LinearParadox <https://github.com/LinearParadox>`__
+  `#803 <https://github.com/scverse/squidpy/pull/803>`__

src/squidpy/read/_utils.py

@@ -4,10 +4,10 @@
 from typing import Any, Optional, Tuple
 
 import numpy as np
-from anndata import AnnData, read_mtx, read_text
+from anndata import AnnData, read_text
 from h5py import File
 from PIL import Image
-from scanpy import read_10x_h5
+from scanpy import read_10x_h5, read_10x_mtx
 
 from squidpy._constants._pkg_constants import Key
 from squidpy._utils import NDArrayA
@@ -48,8 +48,8 @@ def _read_counts(
 
     if count_file.endswith((".csv", ".txt")):
         adata = read_text(path / count_file, **kwargs)
-    elif count_file.endswith(".mtx"):
-        adata = read_mtx(path / count_file, **kwargs)
+    elif count_file.endswith(".mtx.gz"):
+        adata = read_10x_mtx(path, **kwargs)
     else:
         raise NotImplementedError("TODO")