Add octothorpes to disclaimer in exported reserved list

There's no real standard for commented lines in a CSV, but this seems to be the
most well-supported option, so may as well use it.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=211847395

java/google/registry/config/files/nomulus-config-unittest.yaml

@@ -6,6 +6,9 @@ registryPolicy:
     - notification@test.example
     - notification2@test.example
   defaultRegistrarWhoisServer: whois.nic.fakewhois.example
+  reservedTermsExportDisclaimer: |
+    Disclaimer line 1.
+    Line 2 is this 1.
 
 datastore:
   commitLogBucketsNum: 3