Fix #9387: xml: XML Builder ignores custom visitors

So far, XML builder only allows to switch its translator to custom one.
But it does not support to install custom visitor methods.  This allows
to use them expectedly.

CHANGES

@@ -88,6 +88,7 @@ Bugs fixed
 * #9306: Linkcheck reports broken link when remote server closes the connection
   on HEAD request
 * #9280: py domain: "exceptions" module is not displayed
+* #9387: xml: XML Builder ignores custom visitors
 * #9224: ``:param:`` and ``:type:`` fields does not support a type containing
   whitespace (ex. ``Dict[str, str]``)
 * #8945: when transforming typed fields, call the specified role instead of

sphinx/writers/xml.py

@@ -19,7 +19,9 @@ class XMLWriter(BaseXMLWriter):
     def __init__(self, builder: Builder) -> None:
         super().__init__()
         self.builder = builder
-        self.translator_class = self.builder.get_translator_class()
+
+        # A lambda function to generate translator lazily
+        self.translator_class = lambda document: self.builder.create_translator(document)
 
     def translate(self, *args: Any, **kwargs: Any) -> None:
         self.document.settings.newlines = \