Add mappings for bold and italic cal font class - #26419

From the #22056 discussion, it seems using plt.rcParams['font.weight'] = 'bold' seems to be problematic. Using the \mathbfit command to fetch the bold calligraphy fonts could be a way forward (?)

fontsets = ["dejavusans", "dejavuserif", "cm", "stixsans", "stix"]
for x, fs in enumerate(fontsets):
    s = "$\mathrm{%s}: \mathcal{ABCDE} \mathbfit{\mathcal{ABCDE}}$" % (fs)
    ...

Hi @ksunden, I investigated further on this issue and listing my findings on this:

• It is tricky to render the bold cal symbol in LaTeX, however, it provides a mathbfcal command to use bold calligraphic versions of the symbols.
  Reference: https://tex.stackexchange.com/questions/2783/bold-calligraphic-typeface
• There is a mathalpha package that provides the Euler Bold Script or Euler-Math fonts for the bold calligraphic versions.
  

References:

• https://mirror.niser.ac.in/ctan/fonts/euler-math/Euler-Math.pdf
• https://ctan.math.illinois.edu/macros/latex/contrib/mathalpha/doc/mathalpha-doc.pdf

• From my understanding, I think neither DejaVu Sans nor Stix provides the bold mathcal Unicode. Although the Computer Modern font provides bold versions for mathcal from the cmbsy10 font listed here, integrating that results in the following:
  

However, it does not make much sense to add a new font just for Computer Modern, or to add the Euler-math font. So this issue could be closed as expected LaTeX behavior because default LaTeX does not seem to provide it simply either.
As a side note, I could add the cmbsy10 changes here as a reference for the user or maybe an example plot or something (?)

Some more useful references:
https://tug.org/TUGboat/tb33-3/tb105vieth.pdf
https://cs.brown.edu/about/system/managed/latex/doc/euler.pdf
https://tex.stackexchange.com/questions/580904/accessing-all-possible-math-styles-of-the-stix-font