[structure.specifications] replace "paragraph" with "element"

Author: jwakely

source/lib-intro.tex

@@ -497,7 +497,7 @@
 Descriptions of function semantics contain the following elements (as
 appropriate):\footnote{To save space, elements that do not apply to a function are omitted.
 For example, if a function specifies no
-preconditions, there will be no \expects paragraph.}
+preconditions, there will be no \expects element.}
 
 \begin{itemize}
 \item