Print template path chain in TemplateNotFound exception

sphinx/jinja2glue.py

@@ -218,4 +218,4 @@ def get_source(self, environment: Environment, template: str) -> tuple[str, str,
                 return loader.get_source(environment, template)
             except TemplateNotFound:
                 pass
-        raise TemplateNotFound(template)
+        raise TemplateNotFound(f"{template!r} not found in {self.environment.loader.pathchain}")