Change IDN hostname references to refer to RFC 5890 instead of Punycode

README.md

@@ -103,7 +103,7 @@ below are not met.
   * [Requirements for Internet Hosts: Host Names and Numbers](https://tools.ietf.org/html/rfc1123#section-2)\
     (You may need to scroll to Section 2.1.)
   * [Application Techniques for Checking and Transformation of Names](https://tools.ietf.org/html/rfc3696#section-2)
-  * [Internationalized Domain Names in Applications: Punycode Conversion](https://tools.ietf.org/html/rfc5891#section-4.4)
+  * [Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework](https://tools.ietf.org/html/rfc5890)
 * Format "json": [JSON](https://tools.ietf.org/html/rfc8259)
 * Format "url":
   * [URI](https://tools.ietf.org/html/rfc3986)\

rdm-schema.json

@@ -433,7 +433,7 @@
         "type": { "const": "string" },
         "format": {
           "title": "Interpretation format",
-          "description": "This field describes how to interpret the string value. It can be one of the string types defined in \"Table A-15: Data Type Defines\" of the RDM E1.20 specification (or other add-on specifications), one of the defined formats from the JSON Schema Validation specification (https://json-schema.org/draft/2019-09/json-schema-validation.html#rfc.section.7.3), or it can be something manufacturer-specific. It is suggested that a URI or other unique naming convention be used to uniquely identify these. Be aware, however, that anything not defined here may not be understood by a controller or UI. The known string types from E1.20 (and add-ons) include: hostname (https://tools.ietf.org/html/rfc1123#section-2, https://tools.ietf.org/html/rfc3696#section-2, https://tools.ietf.org/html/rfc5891#section-4.4), json (https://tools.ietf.org/html/rfc8259), string, and url (the intent of DS_URL in \"Table A-15\") (https://tools.ietf.org/html/rfc3986, https://tools.ietf.org/html/rfc1738).",
+          "description": "This field describes how to interpret the string value. It can be one of the string types defined in \"Table A-15: Data Type Defines\" of the RDM E1.20 specification (or other add-on specifications), one of the defined formats from the JSON Schema Validation specification (https://json-schema.org/draft/2019-09/json-schema-validation.html#rfc.section.7.3), or it can be something manufacturer-specific. It is suggested that a URI or other unique naming convention be used to uniquely identify these. Be aware, however, that anything not defined here may not be understood by a controller or UI. The known string types from E1.20 (and add-ons) include: hostname (https://tools.ietf.org/html/rfc1123#section-2, https://tools.ietf.org/html/rfc3696#section-2, https://tools.ietf.org/html/rfc5890), json (https://tools.ietf.org/html/rfc8259), string, and url (the intent of DS_URL in \"Table A-15\") (https://tools.ietf.org/html/rfc3986, https://tools.ietf.org/html/rfc1738).",
           "type": "string"
         },
         "pattern": {