[Bug] Wrong syntax highlighting for reStructuredText

Reproducible in vscode.dev or in VS Code Desktop?

• Not reproducible in vscode.dev or VS Code Desktop

Reproducible in the monaco editor playground?

• Not reproducible in the monaco editor playground

Monaco Editor Playground Code

.. math::

.. hello:: asd

.. line-block::

.. line-block:: aaa

.. lineQ-block:: aa
.. lineQQ-block:: aa
.. lineQQQ-block:: aa
.. lineQQQQ-block:: aa

.. lineblock:: aaa

    .. line-block::

Actual Behavior

Half of directives in the example code are treated as comments:

Expected Behavior

All rst directives in the example code should be successfully determined by tokenizer.

According to https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#directives:

Directive types are case-insensitive single words (alphanumerics plus isolated internal hyphens, underscores, plus signs, colons, and periods; no whitespace)

Also note that directive arguments are optional, thus a whitespace after "::" is optional too.

Additional Context

No response

Start with the Monaco Editor playground and the provided reStructuredText example, then inspect how its tokenizer classifies directive names and optional arguments. Compare the actual and expected highlighting for the listed directive forms; done means valid directives are no longer treated as comments.