misc: Minor enhancement to Eq printing

Author: EdCaunt

devito/operator/operator.py

@@ -222,7 +222,7 @@ def _sanitize_exprs(cls, expressions, **kwargs):
         return expressions
 
     @classmethod
-    def _retrieve_opt(cls, expressions, **kwargs):
+    def _retrieve_op(cls, expressions, **kwargs):
         return
 
     @classmethod

devito/types/equation.py

@@ -183,6 +183,9 @@ def xreplace(self, rules):
         return self.func(self.lhs.xreplace(rules), self.rhs.xreplace(rules))
 
     def __str__(self):
+        if self._subdomain is not None:
+            return (f"{self.__class__.__name__}({self.lhs}, {self.rhs},"
+                    f" subdomain={self._subdomain})")
         return f"{self.__class__.__name__}({self.lhs}, {self.rhs})"
 
     __repr__ = __str__