[array.overview] Mention condition of exception

Author: JohelEGP

source/containers.tex

@@ -6123,7 +6123,7 @@
 of a container\iref{container.reqmts} and
 of a reversible container\iref{container.rev.reqmts},
 except that a default
-constructed \tcode{array} object is not empty.
+constructed \tcode{array} object is not empty if $\tcode{N} > 0$.
 An \tcode{array} meets some of the requirements of a sequence
 container\iref{sequence.reqmts}.
 Descriptions are provided here