Add xreplace for Matrix

Author: isuruf

symengine/lib/symengine_wrapper.pyx

@@ -3515,6 +3515,7 @@ cdef class DenseMatrixBase(MatrixBase):
         cdef _DictBasic D = get_dict(*args)
         return self.applyfunc(lambda x: x.subs(D))
 
+    replace = xreplace = subs
 
     @property
     def free_symbols(self):

symengine/tests/test_matrices.py

@@ -566,6 +566,7 @@ def test_immutablematrix():
     X = ImmutableMatrix([[1, 2], [3, 4]])
     Y = ImmutableMatrix([[1, 2], [x, 4]])
     assert Y.subs(x, 3) == X
+    assert Y.xreplace(x, 3) == X
 
     X = ImmutableMatrix([[1, 2], [3, 4]])
     Y = ImmutableMatrix([[5], [6]])