Add escape around 'and' that's considered natural language

This makes sense when thinking of this lstlisting as a quick and dirty way of writing an equation with lots of inline code, and then this 'and' would have been inside \text{...}.

chapters/arrays.tex

@@ -675,7 +675,7 @@ \subsection{Array Concatenation}\doublelabel{array-concatenation}
 Formally, the concatenation \lstinline[mathescape=true]!R = cat($k$, A, B, C, $\ldots$)! is defined as follows.  Let $n$ = \lstinline!ndims(A)! = \lstinline!ndims(B)! = \lstinline!ndims(C)! = \ldots  Then the size of \lstinline!R! is given by
 \begin{lstlisting}[language=modelica,escapechar=!,mathescape=true,frame=none,xleftmargin=1em]
 size(R,$k$) = size(A,$k$) + size(B,$k$) + size(C,$k$) + $\ldots$
-size(R,$j$) = size(A,$j$) = size(B,$j$) = size(C,$j$) = $\ldots$ !for! $1 \leq j \leq n$ and $j \neq k$
+size(R,$j$) = size(A,$j$) = size(B,$j$) = size(C,$j$) = $\ldots$ !for! $1 \leq j \leq n$ !and! $j \neq k$
 \end{lstlisting}
 and the array elements of \lstinline!R! are given by
 \begin{lstlisting}[language=modelica,escapechar=!,mathescape=true,frame=none,xleftmargin=1em]