Add missing glyph for `∪` (U+222A, union)

[cionx]

Description of the new feature/enhancement (with images if possible)

Cascadia provides a glyph for ∩ (U+2229, intersection) but is missing its twin ∪ (U+222A, union). This leads to problems when both characters are in use, e.g., in mathematical writing: either a glyph is missing, or it has to be taken from a fallback font, which may not match Cascadia. The following example is taken from math.stackexchange.com, which uses Cascadia Mono as its monospaced font:

We see that ∪ is taken from a fallback font that doesn’t match Cascadia.

I’d except Cascadia to also provide a glyph for ∪. The above example should then look similar to the following edited version:

Proposed technical implementation details (optional)

To get a suitable glyph for ∪ take the one for ∩ and flip it around, possibly followed by moving the resulting glyph down a bit for visual purposes.