suppress scipy deprecation warnings

scipy will more some scipy.* functions to numpy in scipy 2.0
These warings pop up in networkx 2.2, up to 2.4
and break doctests (but not in Sage code itself).
We suppress them here. This can be removed with networkx 2.5
(not yet released).

src/sage/doctest/forker.py

@@ -849,6 +849,13 @@ def run(self, test, compileflags=None, out=None, clear_globs=True):
         """
         self.setters = {}
         randstate.set_random_seed(0)
+        # scipy 1.18 introduced reprecation warnings on a number of things they are moving to
+        # numpy, e.g. DeprecationWarning: scipy.array is deprecated
+        #             and will be removed in SciPy 2.0.0, use numpy.array instead
+        # This affects networkx 2.2 up and including 2.4
+        # We filter them out here:
+        warnings.filterwarnings('ignore', '.*Deprec.*scipy.*instead',) # cf trac #29425
+
         warnings.showwarning = showwarning_with_traceback
         self.running_doctest_digest = hashlib.md5()
         self.test = test