**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
'description',
        'host',
        'port',
        'is_encrypted',
        'is_extra_encrypted',
    ]
    add_columns = edit_columns = [
        'conn_id',
        'conn_type',
        'description',
        'host',
        'schema',
        'login',
        'password',
        'port',
        'extra',
    ] + extra_fields
    add_form = edit_form = ConnectionForm
    add_template = 'airflow/conn_create.html'
    edit_template = 'airflow/conn_edit.html'
    add_widget = ConnectionFormWidget
    edit_widget = ConnectionFormWidget
    base_order = ('conn_id', 'asc')
    @action('muldelete', 'Delete', 'Are you sure you want to delete selected records?', single=False)
    @auth.has_access(
        [
            (permissions.ACTION_CAN_EDIT, permissions.RESOURCE_DAG),
        ]
    )
    def action_muldelete(self, items):