docs: update release notes

Also move incorrect entry from 18.2 to 18.3

Author: ellemouton

docs/release-notes/release-notes-0.18.2.md

@@ -40,10 +40,6 @@
 ## BOLT Spec Updates
 ## Testing
 ## Database
-
-* [Fixed](https://github.com/lightningnetwork/lnd/pull/8854) pagination issues 
-  in SQL invoicedb queries.
-
 ## Code Health
 ## Tooling and Documentation
 

docs/release-notes/release-notes-0.18.3.md

@@ -100,7 +100,16 @@
   invoice database. Invoices with incorrect expiry values will be updated to
   24-hour expiry, which is the default behavior in LND.
 
+* [Fixed](https://github.com/lightningnetwork/lnd/pull/8854) pagination issues
+  in SQL invoicedb queries.
+
 ## Code Health
+
+* [Move graph building and
+  maintaining](https://github.com/lightningnetwork/lnd/pull/8848) duties from
+  the `routing.ChannelRouter` to the new `graph.Builder` sub-system and also
+  remove the `channeldb.ChannelGraph` pointer from the `ChannelRouter`.
+
 ## Tooling and Documentation
 
 # Contributors (Alphabetical Order)