support MatrixExpr

Author: Zeroto521

src/pyscipopt/matrix.pxi

@@ -18,7 +18,7 @@ def _is_number(e):
 
 
 def _matrixexpr_richcmp(self, other, op):
-    if not _is_number(other) or not isinstance(other, (Expr, np.ndarray)):
+    if not (_is_number(other) or isinstance(other, (Expr, MatrixExpr, np.ndarray))):
         raise TypeError(f"Unsupported type {type(other)}")
 
     if op == 1: # <=