(nil and t): Do not use `iff' in documentation.

diff --git a/lispref/intro.texi b/lispref/intro.texi
index 35566603b7cb12aa922720676b6b7ed49e68a936..ed0fd1c0699f6cae2ecce02d810a3c8e4edb371d 100644 (file)
--- a/lispref/intro.texi
+++ b/lispref/intro.texi
@@ -213,7 +213,7 @@ values results in a @code{setting-constant} error.  @xref{Constant
 Variables}.
 
 @defun booleanp object
-Return non-nil iff @var{object} is one of the two canonical boolean
+Return non-nil if @var{object} is one of the two canonical boolean
 values: @code{t} or @code{nil}.
 @end defun