Backport PR matplotlib#25268 on branch v3.7.x (Fix import of styles with relative path)

Fix import of styles with relative path

(cherry picked from commit ee7d75e)

Conflict was caused by pyupgrade changing IOError to OSError (which are
aliases of each other since py3.3)

Author: oscargus

lib/matplotlib/style/core.py

@@ -153,7 +153,7 @@ def use(style):
                     path = (importlib_resources.files(pkg)
                             / f"{name}.{STYLE_EXTENSION}")
                     style = _rc_params_in_file(path)
-                except (ModuleNotFoundError, IOError) as exc:
+                except (ModuleNotFoundError, OSError, TypeError) as exc:
                     # There is an ambiguity whether a dotted name refers to a
                     # package.style_name or to a dotted file path.  Currently,
                     # we silently try the first form and then the second one;

lib/matplotlib/tests/test_style.py

@@ -205,3 +205,5 @@ def test_style_from_module(tmp_path, monkeypatch):
     assert mpl.rcParams["lines.linewidth"] == 42
     mpl.style.use("mpl_test_style_pkg.mplstyle")
     assert mpl.rcParams["lines.linewidth"] == 84
+    mpl.style.use("./mpl_test_style_pkg.mplstyle")
+    assert mpl.rcParams["lines.linewidth"] == 84