chore: provide detailed note for sentry endpoint settings (#3780)

Follow up for #3747

Author: aldy505

sentry/sentry.conf.example.py

@@ -345,8 +345,12 @@ def get_internal_network():
 # Sentry Endpoint Settings #
 ############################
 
-# URI Prefixes for generating DSN URLs
-# (default is URL_PREFIX)
+# If your Sentry installation has different hostnames for ingestion and web UI,
+# in which your web UI is accessible via private corporate network, yet your
+# ingestion hostname is accessible from the public internet, you can uncomment
+# this following options in order to have the ingestion hostname rendered
+# correctly on the SDK configuration UI.
+#
 # SENTRY_ENDPOINT = "https://sentry.ingest.example.com"
 
 #################