lnd: update docs on nodeann addresses retaining

sample-lnd.conf

@@ -212,6 +212,14 @@
 ; advertise your node, this value doesn't need to be set. Unless specified
 ; (with host:port notation), the default port (9735) will be added to the
 ; address.
+;
+; NOTE: If you previously set one or more `externalip` entries and later
+; remove `externalip` entirely from the config, lnd will continue to advertise
+; the last known addresses from the previous run (they are stored with your node
+; information). To stop advertising them, remove those addresses explicitly
+; using the peers RPC/CLI, for example:
+;   `lncli peers updatenodeannouncement --address_remove=1.2.3.4:9735`
+; A restart is not required, a new node announcement will be broadcasted.
 ; externalip=
 ;
 ; Instead of explicitly stating your external IP address, you can also enable
@@ -553,13 +561,19 @@
 
 ; The alias your node will use, which can be up to 32 UTF-8 characters in
 ; length.
-; Default:
+; Default is the first 10-bytes of the node's pubkey. 
+; 
+; NOTE: If this is not set lnd will use the last known alias from the previous
+; run.
 ;   alias=
 ; Example:
 ;   alias=My Lightning ☇
 
 ; The color of the node in hex format, used to customize node appearance in
 ; intelligence services.
+;
+; NOTE: If this is not set or is set to the default (#3399FF) lnd will use the 
+; last known color from the previous run.
 ; color=#3399FF
 
 ; The maximum duration that the server will wait before timing out reading