Thanks for the advice, @mmerlinn!
The text in the page's font shows the Trokendi page using regular parentheses, although it is certainly possible that a code was used when editing the name of the page, and then the character was converted to the output.
I did a little test and discovered that the HTML entity names (& lpar; & rpar;) pass the validation, but they are not translated into the characters of the page. I tried using the entity numbers (& # 40; & # 41), but the validation does not allow me to use the number sign. I also tried some variations on the Unicode symbol ( u0028 u0029), but the code showed instead of the symbol (like entity numbers).
This DID gave me the idea to try other characters, which produced an interesting result. It turns out that the parentheses "ornament" characters are allowed. So, although I could not use the normal parentheses, I was able to use: ❨ and ❩ instead of (y). In the same way, you can use the special characters in bold.
So, that may be a reasonable alternative solution (counting that as a victory!), But it does not answer the question of how our other example used regular parentheses.
Any other idea? Maybe I just did not enter the correct character entity codes? I know there are things like @ codes that you can use to get interesting results. Could there be a code that allows me to use character entities?
Again, thanks for your help!