fix(ext_jinja2): refactor hard-coded reference to jinja2 template handler

Issue: #749

Author: derks

CHANGELOG.md

@@ -4,7 +4,8 @@
 
 Bugs:
 
-- None
+- `[ext_jinja2]` Refactor hard-coded reference to `jinja2` template handler.
+  - [Issue #749](https://github.com/datafolklabs/cement/issues/749)
 
 Features:
 

cement/ext/ext_jinja2.py

@@ -34,6 +34,9 @@ class Jinja2OutputHandler(OutputHandler):
     Please see the developer documentation on
     :cement:`Output Handling <dev/output>`.
 
+    This class has an assumed depency on it's associated Jinja2TemplateHandler.
+    If sub-classing, you must also sub-class/implement the Jinja2TemplateHandler
+    and give it the same label.
     """
 
     class Meta(OutputHandler.Meta):
@@ -48,7 +51,7 @@ def __init__(self, *args: Any, **kw: Any) -> None:
 
     def _setup(self, app: App) -> None:
         super(Jinja2OutputHandler, self)._setup(app)
-        self.templater = self.app.handler.resolve('template', 'jinja2', setup=True)  # type: ignore
+        self.templater = self.app.handler.resolve('template', self._meta.label, setup=True)  # type: ignore
 
     def render(self, data: Dict[str, Any], template: str = None, **kw: Any) -> str:  # type: ignore
         """