Rendering errors (<chem> and <math>)

Note from @BoboTiG: issue tightly coupled to #1183, interesting details can be found there too.

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I did a fresh download and render of the EN wiktionary today, and got the following errors:

>>> Loading data/en/data_wikicode-20220120.json ...
>>> Loaded 1,038,672 words from data/en/data_wikicode-20220120.json
<chem> ERROR with ^-N=\overset{+}N=N^- in [azide]
<math> ERROR with \begin{align}\frac{\pi}{2} & = \prod_{n=1}^{\infty} \frac{ 4n^2 }{ 4n^2 - 1 } = \prod_{n=1}^{\infty} \left(\frac{2n}{2n-1} \cdot \frac{2n}{2n+1}\right) \\[6pt]& = \Big(\frac{2}{1} \cdot \frac{2}{3}\Big) \cdot \Big(\frac{4}{3} \cdot \frac{4}{5}\Big) \cdot \Big(\frac{6}{5} \cdot \frac{6}{7}\Big) \cdot \Big(\frac{8}{7} \cdot \frac{8}{9}\Big) \cdot \; \cdots \\\end{align} in [Wallis product]
<math> ERROR with \begin{align}a_0 &+ a_1x + a_2x^2 + a_3x^3 + \cdots + a_nx^n \\ &= a_0 + x \bigg(a_1 + x \Big(a_2 + x \big(a_3 + \cdots + x(a_{n-1} + x \, a_n) \cdots \big) \Big) \bigg).\end{align} in [Horner's rule]
<math> ERROR with \frac = \frac in [circle of Apollonius]
<math> ERROR with \begin{align}\rho(g, h) (0,x_1,\ldots,x_k) &= g(x_1,\ldots,x_k) \\\rho(g, h) (y+1,x_1,\ldots,x_k) &= h(y,\rho(g, h) (y,x_1,\ldots,x_k),x_1,\ldots,x_k)\,\end{align} in [primitive recursion]
>>> Saved 697,169 words into data/en/data-20220120.json
>>> Render done!

[lasconic]

I was also curious if svg could be used on Kobo. And it can ! dicthtml-en-en.zip (11,819 bytes)

dvioptions = [ "-d -1", ]
    with BytesIO() as buf, BytesIO() as im:
        preview(
            f"${expr}$",
            output="svg",
            viewer="BytesIO",
            outputbuffer=buf,
            dvioptions=dvioptions,
            packages=tuple(packages),
        )

        buf.seek(0)
        raw = buf.read()

    return f'<img style="{IMG_CSS}" src="data:image/svg+xml;base64,{b64encode(raw).decode()}"/>'

PNG:

GIF

SVG

[lasconic]

dictgen mentions GIF and JPG https://pgaskin.net/dictutil/dictgen/ In theory, Kobo should support PNG https://help.kobo.com/hc/fr/articles/360017763713-Formats-de-fichiers-pris-en-charge-par-votre-application-Kobo-eReader-et-Kobo-Books but not sure if the support is included for dictionaries.