Explore ways to avoid ignoring line-height from custom pygments themes

[pradyunsg]

Discussed in #438

^{Originally posted by asmeurer May 11, 2022}
In our custom pygments theme for SymPy, we set the line-height attribute using _pre_style: https://github.com/sympy/sympy/blob/68c37df362e8585d72fc7ef490013bb8eff16e3e/doc/src/_pygments/styles.py#L25-L29

However, this is being ignored by the docs

We need this so that Unicode pretty printed output doesn't add extra space between lines. See for example https://docs.sympy.org/dev/tutorial/printing.html#unicode-pretty-printer and compare to our previous theme which set this attribute correctly https://docs.sympy.org/latest/tutorial/printing.html#unicode-pretty-printer

I can work around this by adding it to the custom.css, but it seems preferable to include it in the pygments theme since pygments allows this.