Replace <server-name> with example.com

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2

@@ -1962,7 +1962,7 @@ saml2_config:
 #
 #   idp_icon: An optional icon for this identity provider, which is presented
 #       by clients and Synapse's own IdP picker page. If given, must be an
-#       MXC URI of the format mxc://<server-name>/<media-id>. (An easy way to
+#       MXC URI of the format mxc://example.com/<media-id>. (An easy way to
 #       obtain such an MXC URI is to upload an image to an (unencrypted) room
 #       and then copy the "url" from the source of the event.)
 #