Incorrect level of headers in the generated jupyter book

[ambipomyan]

For now \section{}, \subsection{} and \subsubsection{} are replaced by #, ## and ### for md headers respectively.
However, the headers are proved triggering warnings when generating jupyter book.
The detailed warnings are attached below.
This bug is caused by the contents construction of LaTeX files and the solid header arrangement rule of jupyter book.
Some sections are distributed into several files, that is, the first level header of a certain LaTeX file could be \subsection{} thus being replaced by ##.
Then, for jupyter book, it is not allowed, for the highest level header in a single page should always be #.

/Users/jkkl/Desktop/Examples/util/tex2notebook/tmp/contents/Examples_SIMD.ipynb:10003: WARNING: Non-consecutive header level increase; 0 to 2 [myst.header]
/Users/jkkl/Desktop/Examples/util/tex2notebook/tmp/contents/Examples_SIMD.ipynb:200002: WARNING: Non-consecutive header level increase; 0 to 2 [myst.header]
/Users/jkkl/Desktop/Examples/util/tex2notebook/tmp/contents/Examples_SIMD.ipynb:280002: WARNING: Non-consecutive header level increase; 0 to 2 [myst.header]
/Users/jkkl/Desktop/Examples/util/tex2notebook/tmp/contents/Examples_acquire_release.ipynb:10002: WARNING: Non-consecutive header level increase; 0 to 2 [myst.header]
/Users/jkkl/Desktop/Examples/util/tex2notebook/tmp/contents/Examples_affinity.ipynb:10002: WARNING: Non-consecutive header level increase; 0 to 2 [myst.header]
/Users/jkkl/Desktop/Examples/util/tex2notebook/tmp/contents/Examples_affinity_display.ipynb:10002: WARNING: Non-consecutive header level increase; 0 to 2 [myst.header]
/Users/jkkl/Desktop/Examples/util/tex2notebook/tmp/contents/Examples_affinity_query.ipynb:10002: WARNING: Non-consecutive header level increase; 0 to 2 [myst.header]
/Users/jkkl/Desktop/Examples/util/tex2notebook/tmp/contents/Examples_allocators.ipynb:10002: WARNING: Non-consecutive header level increase; 0 to 2 [myst.header]
/Users/jkkl/Desktop/Examples/util/tex2notebook/tmp/contents/Examples_array_sections.ipynb:10002: WARNING: Non-consecutive header level increase; 0 to 2 [myst.header]
/Users/jkkl/Desktop/Examples/util/tex2notebook/tmp/contents/Examples_array_shaping.ipynb:10002: WARNING: Non-consecutive header level increase; 0 to 2 [myst.header]