icons not shown correctly in rst toctree

[jhj0411jhj]

Describe the bug

context When I write icons in rst toctree:

..  toctree::
    :caption: Table of content
    :maxdepth: 2
    :titlesonly:

    Quick Start :octicon:`rocket;1em` <quick_start/quick_start>

expectation I expected icon to occur in the side bar.

bug But instead the raw text is shown.

Reproduce the bug

write toctree as above

List your environment

myst-parser                   0.18.1
furo                          2022.12.7
pydata-sphinx-theme           0.8.1
sphinx-basic-ng               1.0.0b1
sphinx-book-theme             0.3.3
sphinx-copybutton             0.5.1
sphinx_design                 0.3.0
sphinx-hoverxref              1.3.0
sphinx-notfound-page          0.8.3
sphinx-rtd-theme              1.1.1
sphinxcontrib-applehelp       1.0.2
sphinxcontrib-devhelp         1.0.2
sphinxcontrib-htmlhelp        2.0.0
sphinxcontrib.jquery          3.0.0
sphinxcontrib-jsmath          1.0.1
sphinxcontrib-qthelp          1.0.3
sphinxcontrib-serializinghtml 1.1.5

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[guideloom]

I just came here to report the same thing. Would be GREAT to get this working.

[drammock]

I suspect that this has the same root cause as #66, namely it is a limitation of sphinx that has been raised upstream (https://github.com/sphinx-doc/sphinx/issues/8068) and milestoned for "some future version" of sphinx (i.e., probably not supported anytime soon)