\boldsymbol not italic for textords such as Greek

[edemaine]

Fix #2225: \boldsymbol{\Omega} will now produce a bold upright Omega instead of a bold italic Omega. This only affects textord symbols within \boldsymbol, mimicking the no-font case in makeOrd which distinguishes textord from mathord in a similar way.

Demo

\Omega\boldsymbol{\Omega}\mathnormal{\Omega}\mathit{\Omega}

LaTeX (via quicklatex):

With this PR:

Without this PR:

Changed screenshot

Here's the diff on the changed screenshot BoldSymbol (red is old, green is new):

Here's the same example rendered by LaTeX, to confirm this is a fix:

Related PRs

This conflicts slightly with a one-line edit in #2156. But it actually replaces that explicit check for /[0-9]/, because these characters are already textords. So it makes that nice PR even more beautiful.

[ronkok]

I may be stepping a bit out of my lane here, reviewing other people's code, but this looks good to me.

I have also verified that the MathML has made the correct change. Before this PR, KaTeX returned <span style="margin-right: 0.04835em;" class="mord boldsymbol">Ω</span>. Now it returns <span class="mord mathbf">Ω</span>.

[edemaine]

Thanks for the review! Luckily it's just a one-line change, and can only affect \boldsymbol, and it's still not perfect (#2291), but I think this is a strict improvement. I see this Greek upright issue a lot in the wild (in my project), so I'm happy to see it fixed!

[ronkok]

coauthor looks like a neat project. Real-time collaboration is a powerful thing.