Update the definition of the Z pack format code (#4696)

Author: 27pchrisl

reference/misc/functions/pack.xml

@@ -166,7 +166,7 @@
           </row>
           <row>
            <entry>Z</entry>
-           <entry>NUL-padded string</entry>
+           <entry>NUL-terminated (ASCIIZ) string, will be NUL padded</entry>
           </row>
           <row>
            <entry>@</entry>