**Apache Airflow version**: 2.1.1

**What happened**:

The rendered templates screen doesn't show the operator arguments for TaskFlow API operators.
![image](https://user-images.githubusercontent.com/72943478/125486179-f6dde0be-9f60-4aca-831a-5cfd16e7f006.png)

**What you expected to happen**:

Should show the arguments after any templates have been rendered.

**How to reproduce it**:

Will happen for any `@task` decorated operator.

**Anything else we need to know**:

This issue appears on a number of operators.  Possible solution is to modify the "get_python_source" in utils/code_utils.py to handle list and dict. This would cause any operator that using py as the renderer to handle lists and dicts.  Possibly something like:
```
    if isinstance(x, list):
        return [str(v) for v in x]

    if isinstance(x, dict):
        return {k: str(v) for k, v in x.items()}
```
The converting values to strings seems necessary in order to avoid errors when this is passed to the pygments lexer.
![image](https://user-images.githubusercontent.com/72943478/125494716-01cf0c11-9e5f-45fa-afe2-4f99409edefc.png)

airflow/www/views.py
table = [
                (section, key, value, source)
                for section, parameters in conf.as_dict(True, True).items()
                for key, (value, source) in parameters.items()
            ]
        else:
            config = (
                "# Your Airflow administrator chose not to expose the "
                "configuration, most likely for security reasons."
            )
            table = None
        if raw:
            return Response(response=config, status=200, mimetype="application/text")
        else:
            code_html = Markup(
                highlight(
                    config,
                    lexers.IniLexer(),  
                    HtmlFormatter(noclasses=True),
                )
            )
            return self.render_template(
                'airflow/config.html',
                pre_subtitle=settings.HEADER + "  v" + airflow.__version__,
                code_html=code_html,
                title=title,
                subtitle=subtitle,
                table=table,
            )
class RedocView(AirflowBaseView):