Update dangling Cluster references in reference.conf to Session (#1596)

Author: akhaku

core/src/main/resources/reference.conf

@@ -1041,7 +1041,7 @@ datastax-java-driver {
     # an incompatible node joins the cluster later, connection will fail and the driver will force
     # it down (i.e. never try to connect to it again).
     #
-    # You can check the actual version at runtime with Cluster.getContext().getProtocolVersion().
+    # You can check the actual version at runtime with Session.getContext().getProtocolVersion().
     #
     # Required: no
     # Modifiable at runtime: no
@@ -1925,7 +1925,7 @@ datastax-java-driver {
       max-events = 20
     }
 
-    # Options relating to schema metadata (Cluster.getMetadata.getKeyspaces).
+    # Options relating to schema metadata (Session.getMetadata.getKeyspaces).
     # This metadata is exposed by the driver for informational purposes, and is also necessary for
     # token-aware routing.
     schema {
@@ -1934,7 +1934,7 @@ datastax-java-driver {
       #
       # Required: yes
       # Modifiable at runtime: yes, the new value will be used for refreshes issued after the
-      #   change. It can also be overridden programmatically via Cluster.setSchemaMetadataEnabled.
+      #   change. It can also be overridden programmatically via Session.setSchemaMetadataEnabled.
       # Overridable in a profile: no
       enabled = true
 
@@ -2013,7 +2013,7 @@ datastax-java-driver {
       }
     }
 
-    # Whether token metadata (Cluster.getMetadata.getTokenMap) is enabled.
+    # Whether token metadata (Session.getMetadata.getTokenMap) is enabled.
     # This metadata is exposed by the driver for informational purposes, and is also necessary for
     # token-aware routing.
     # If this is false, it will remain empty, or to the last known value. Note that its computation