scripts: T4269: node.def generator should automatically add default values

Since introducing the XML <defaultValue> node it was common, but redundant,
practice to also add a help string indicating which value would be used as
default if the node is unset.

This makes no sense b/c it's duplicated code/value/characters and prone to
error. The node.def scripts should be extended to automatically render the
appropriate default value into the CLI help string.

For e.g. SSH the current PoC renders:

$ cat templates-cfg/service/ssh/port/node.def
  multi:
  type: txt
  help: Port for SSH service (default: 22)
  val_help: u32:1-65535; Numeric IP port
  ...

Not all subsystems are already migrated to get_config_dict() and make use of
the defaults() call - those subsystems need to be migrated, first before the new
default is added to the CLI help.

1 files changed, 2 insertions, 2 deletions

diff --git a/interface-definitions/include/interface/dhcpv6-options.xml.i b/interface-definitions/include/interface/dhcpv6-options.xml.i
index d1abf4a90..08e4f5e0a 100644
--- a/interface-definitions/include/interface/dhcpv6-options.xml.i
+++ b/interface-definitions/include/interface/dhcpv6-options.xml.i
@@ -57,10 +57,10 @@
           <children>
             <leafNode name="address">
               <properties>
-                <help>Local interface address assigned to interface</help>
+                <help>Local interface address assigned to interface (default: EUI-64)</help>
                 <valueHelp>
                   <format>&gt;0</format>
-                  <description>Used to form IPv6 interface address (default: EUI-64)</description>
+                  <description>Used to form IPv6 interface address</description>
                 </valueHelp>
                 <constraint>
                   <validator name="numeric" argument="--non-negative"/>