Fixup: introduce what 'n' is before using it.

Author: Dawn Perchik

source/declarations.tex

@@ -4366,7 +4366,8 @@
 Let $x_1$, $\dotsc$, $x_k$ be
 the elements of the \grammarterm{expression-list}.
 If the destination type is an array of unknown bound,
-it is defined as having $k$ elements.
+it is defined as having $k$ elements;
+either way, let $n$ denote the array size.
 If $k$ is greater than the size of the array,
 the program is ill-formed.
 Otherwise, the $i^\text{th}$ array element is copy-initialized with