It's a hard-to-win situation: sometimes you <i>want</i> to
apply html tags to the text you're typing, sometimes you don't.
Even <pre> doesn't do what we need, it only switches to
a fixed-space font and gives special meaning to whitespace chars.
The only fix I see is a completely separate textarea that has
htmlentitles() applied to it before display. This would have its
own set of problems, primarily in terms of referencing between
your prose in the first textarea and your code in the second
textarea. But it's basically what you get in most of the dead-
trees programming journals like Dr. Dobbs and C/C++ Users
Journal ("As shown in figure 4, blah blah...")