[allocator.requirements] Use code font when referring to std::array

Author: jwakely

source/lib-intro.tex

@@ -1929,7 +1929,7 @@
 difference, the type of the size of objects in this allocation model, as well
 as the memory allocation and deallocation primitives for it. All of the
 string types\iref{strings},
-containers\iref{containers} (except array),
+containers\iref{containers} (except \tcode{array}),
 string buffers and string streams\iref{input.output}, and
 \tcode{match_results}\iref{re} are parameterized in terms of
 allocators.