[devel] Fixed a small typo in the manual.

libpng.3

diff --git a/libpng.3 b/libpng.3
index 059e89a..3f46157 100644
--- a/libpng.3
+++ b/libpng.3
@@ -4358,7 +4358,7 @@
 PNG_NO_USE_READ_MACROS before including png.h.  Notice that this is
 only supported from 1.5.0 -defining PNG_NO_USE_READ_MACROS prior to 1.5.0
  will lead to a link failure.
-%15%
+
 B. Changes to the build and configuration of libpng
 
 Details of internal changes to the library code can be found in the CHANGES