highlight_options is not working

[tk0miya]

Describe the bug
highlight_options is not working

To Reproduce

# conf.py
highlight_language = 'php'
highlight_options = {'startinline': True}

# index.rst
.. code-block:: php

   echo "hello world";

.. code-block::

   echo "hello world";

But startinline option does not effect to the HTML and LaTeX output.

Expected behavior
The highlight_options works fine.

Your project
No

Screenshots
No

Environment info

• OS: Mac
• Python version: 3.8.3
• Sphinx version: HEAD of 3.x
• Sphinx extensions: No
• Extra tools: No

Additional context
No