Document missing enumeration value

Add missing Key Tab in
/org.openoffice.Office.Writer/AutoFunction/Completion/AcceptKey

(cherry picked from commit 4ff43c2b)

Conflicts:
	officecfg/registry/schema/org/openoffice/Office/Writer.xcs

Change-Id: I3441a9b97f3e74c115bde84da9a1c85f9c901185

officecfg/registry/schema/org/openoffice/Office/Writer.xcs

@@ -4647,6 +4647,11 @@
                 <desc>KeyRight</desc>
               </info>
             </enumeration>
+            <enumeration oor:value="1282"> <!-- 0x502 -->
+              <info>
+                <desc>KeyTab</desc>
+              </info>
+            </enumeration>
             <enumeration oor:value="1284">
               <!-- 0x504 -->
               <info>