lnd: update docs on nodeann addresses retaining

diff --git a/config.go b/config.go
index 85cdc09..6d5bc54 100644
--- a/config.go
+++ b/config.go
@@ -339,7 +339,7 @@ type Config struct {
 	RawRPCListeners   []string `long:"rpclisten" description:"Add an interface/port/socket to listen for RPC connections"`
 	RawRESTListeners  []string `long:"restlisten" description:"Add an interface/port/socket to listen for REST connections"`
 	RawListeners      []string `long:"listen" description:"Add an interface/port to listen for peer connections"`
-	RawExternalIPs    []string `long:"externalip" description:"Add an ip:port to the list of local addresses we claim to listen on to peers. If a port is not specified, the default (9735) will be used regardless of other parameters"`
+	RawExternalIPs    []string `long:"externalip" description:"Add an ip:port (local addresses we listen on) to advertise to the network (default port 9735 is used if port is not specified). Note: Removing this option does not clear previously advertised addresses; remove them with 'lncli peers updatenodeannouncement --address_remove=host:port'."`
 	ExternalHosts     []string `long:"externalhosts" description:"Add a hostname:port that should be periodically resolved to announce IPs for. If a port is not specified, the default (9735) will be used."`
 	RPCListeners      []net.Addr
 	RESTListeners     []net.Addr
diff --git a/sample-lnd.conf b/sample-lnd.conf
index 6b2ca8a..506b999 100644
--- a/sample-lnd.conf
+++ b/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