[tex-k] typo A332

[胡亚捷 (Hu Yajie)]

Oops, I forgot to mention that entry C251 of errata.tex,

      22.1 (a) If and only if n is an integer between 0 and 255. (b) If and
    only if s is a string of length 1.

lacks a dot after "22.1", according to the format of MFbook Appendix A.

Also, page C155 tells us that a <statement list> is something like

    x = 1; y = 2;

including the final semicolon. The answer to exercise 18.13 speaks of
hide(<statement list>), which is wrong because you can omit the final
semicolon when using hide():

    hide(x = 1; y = 2)

Therefore I proposed changing it to hide(<statements>), because
<statements> isn't rigorously defined and can be used informally
(as on C259--C260). It seems that you misinterpreted my report and
discovered another bug concerning <statement list> back in 2020 :)