[res.on.functions] Use regular "behavior is undefined" words of power (#5513)

RedBeard0531 · web-flow · commit 10a20b22491f · 2022-06-09T18:52:42.000+02:00
diff --git a/source/lib-intro.tex b/source/lib-intro.tex
@@ -3172,7 +3172,7 @@
 on the implementation.
 
 \pnum
-In particular, the effects are undefined in the following cases:
+In particular, the behavior is undefined in the following cases:
 
 \begin{itemize}
 \item
