documentation: Adds missing default attributes.

The configObject tag contains a default attribute which
allows the default value to be specified, if applicable.
This allows for the default value to show up specially on
the wiki in a way that is clear to users.

There are a couple places in the tree where default values
are included in the description as opposed to as attributes,
which means these can't be parsed specially for the wiki.
These are changed to use the attribute instead of being
included in the text description.

ASTERISK-29898 #close

Change-Id: I9d7ea08f50075f41459ea7b76654906b674ec755

main/cdr.c

@@ -90,18 +90,18 @@
 					of use when debugging CDR behavior.</para>
 					</description>
 				</configOption>
-				<configOption name="enable">
+				<configOption name="enable" default="yes">
 					<synopsis>Enable/disable CDR logging.</synopsis>
 					<description><para>Define whether or not to use CDR logging. Setting this to "no" will override
-					any loading of backend CDR modules.  Default is "yes".</para>
+					any loading of backend CDR modules.</para>
 					</description>
 				</configOption>
-				<configOption name="channeldefaultenabled">
+				<configOption name="channeldefaultenabled" default="yes">
 					<synopsis>Whether CDR is enabled on a channel by default</synopsis>
 					<description><para>Define whether or not CDR should be enabled on a channel by default.
 					Setting this to "yes" will enable CDR on every channel unless it is explicitly disabled.
 					Setting this to "no" will disable CDR on every channel unless it is explicitly enabled.
-					Default is "yes".</para>
+					</para>
 					<para>Note that CDR must still be globally enabled (<literal>enable = yes</literal>) for this
 					option to have any effect. This only applies to whether CDR is enabled or disabled on
 					newly created channels, which can be changed in the dialplan during a call.</para>

res/res_ari.c

@@ -96,12 +96,12 @@
 						<ref type="link">https://wiki.asterisk.org/wiki/display/AST/Asterisk+Builtin+mini-HTTP+Server</ref>
 					</see-also>
 				</configOption>
-				<configOption name="websocket_write_timeout">
+				<configOption name="websocket_write_timeout" default="100">
 					<synopsis>The timeout (in milliseconds) to set on WebSocket connections.</synopsis>
 					<description>
 						<para>If a websocket connection accepts input slowly, the timeout
 						for writes to it can be increased to keep it from being disconnected.
-						Value is in milliseconds; default is 100 ms.</para>
+						Value is in milliseconds.</para>
 					</description>
 				</configOption>
 				<configOption name="pretty">

res/res_pjsip.c

@@ -1795,12 +1795,12 @@
 					or the <replaceable>wss</replaceable> protocols.</para></note>
 					</description>
 				</configOption>
-				<configOption name="websocket_write_timeout">
+				<configOption name="websocket_write_timeout" default="100">
 					<synopsis>The timeout (in milliseconds) to set on WebSocket connections.</synopsis>
 					<description>
 						<para>If a websocket connection accepts input slowly, the timeout
 						for writes to it can be increased to keep it from being disconnected.
-						Value is in milliseconds; default is 100 ms.</para>
+						Value is in milliseconds.</para>
 					</description>
 				</configOption>
 				<configOption name="allow_reload" default="no">