doc: fix typo in release notes

Bruce Momjian <bruce@momjian.us>

Commit: 1cccce50f374cfc6081850aedce8eb0f8b274bc5
Author: Bruce Momjian <bruce@momjian.us>
Date: 2013-10-09T12:44:52Z
Releases: 9.4.0
doc:  fix typo in release notes

Backpatch through 8.4

Per suggestion by Amit Langote

Files