[vala] manual: Update from wiki.gnome.org

[Rico Tzschichholz <ricotz src gnome org>]

commit c309dfd8bba3d6ce5c81277061a045466bddcd3e
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Mon Feb 17 11:00:46 2020 +0100

    manual: Update from wiki.gnome.org

 doc/manual/manual.xml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/doc/manual/manual.xml b/doc/manual/manual.xml
index e15c9374d..54613f608 100644
--- a/doc/manual/manual.xml
+++ b/doc/manual/manual.xml
@@ -2279,7 +2279,8 @@
 <para> <emphasis role="strong">Description (optional)</emphasis></para></entry></row><row rowsep="1"><entry 
colsep="1" rowsep="1">
 <para>array_length</para></entry><entry colsep="1" rowsep="1">
 <para>delegate, field, property, method, parameter</para></entry><entry colsep="1" rowsep="1">
-<para>bool</para></entry><entry colsep="1" rowsep="1"/></row><row rowsep="1"><entry colsep="1" rowsep="1">
+<para>bool</para></entry><entry colsep="1" rowsep="1"/></row><row rowsep="1"><entry colsep="1" 
nameend="col_3" namest="col_0" rowsep="1">
+<para> If the array length is unknown, setting array_length = false in the CCode attribute will cause Vala 
to set the array's .length property to -1 and not pass the length when used as a 
parameter.</para></entry></row><row rowsep="1"><entry colsep="1" rowsep="1">
 <para>array_length_cname</para></entry><entry colsep="1" rowsep="1">
 <para>field</para></entry><entry colsep="1" rowsep="1">
 <para>string</para></entry><entry colsep="1" rowsep="1"/></row><row rowsep="1"><entry colsep="1" rowsep="1">