Sub and superscript numbers

I get an error message that a subscript 2 is not accepted as a word character; maybe the same applies to superscript 2 and 3. Why?
Words like CO2 had better been written as CO₂, don’t you agree? But it requires a code change.


If everyone agrees, someone has to update the code. By the way… should word characters not be a per language setting or data file?

By the way, It looks alike words with a number in them are ignored for spelling anyway. At least in LibreOffice, unless one changes the option and switch checking on. After that, CO2 and CO₂ are accepted when CO2 is in the LT dictionary. But then, CO2 is accpeted just as well, which is less than optimal.

So I think I will add all words using CO2 in the dictionary, and add u rule that states that actually a subscript should be used. But that rule might then also be triggered when it is already a subscript…
I will test that.