Problem

Just browsed the available mathematical operators and compared with the ones defined.

(One can probably do a similar thing with other groups of symbols.)

Proposed solution

The following are missing (as in not defined intex2uni in_mathtext_data.py, in hex):

2206 220a 220c 220d 220e 221b 221c 221f 2231 2232 2233 2236 2239223a 223f 2246 226d 2274 2275 2278 2279 228c 229c 22a6 22ab 22b922bd 22be 22bf 22d5 22e0 22e1 22e2 22e3 22e4 22e5 22f2 22f3 22f422f5 22f6 22f7 22f8 22f9 22fa 22fb 22fc 22fd 22fe 22ff

For the corresponding symbols, see:https://www.compart.com/en/unicode/block/U+2200

For LaTeX names, see:https://tug.ctan.org/info/symbols/comprehensive/symbols-a4.pdf

One should probably be a bit discriminate when adding these, but at least those in standard LaTeX (like0x2206 =\triangle) and those from AMS should be supported.