Render the template source with the context given.

    Arguments:
        source: The template source code.
        context: The variables to pass to the template.

async def render_template_string(source: str, **context: Any) -> str:
    """Render the template source with the context given.

    Arguments:
        source: The template source code.
        context: The variables to pass to the template.
    """
    await current_app.update_template_context(context)
    template = current_app.jinja_env.from_string(source)
    return await _render(template, context)