hvcat doc example fixed

hvcat doc example was not working 
I changed it to one that does.

doc/stdlib/arrays.rst

@@ -396,7 +396,7 @@ Indexing, Assignment, and Concatenation
 
    .. Docstring generated from Julia source
 
-   Horizontal and vertical concatenation in one call. This function is called for block matrix syntax. The first argument specifies the number of arguments to concatenate in each block row. For example, ``[a b;c d e]`` calls ``hvcat((2,3),a,b,c,d,e)``\ .
+   Horizontal and vertical concatenation in one call. This function is called for block matrix syntax. The first argument specifies the number of arguments to concatenate in each block row. For example, ``[a b;c d]`` calls ``hvcat((2,2),a,b,c,d)``\ .
 
    If the first argument is a single integer ``n``\ , then all block rows are assumed to have ``n`` block columns.