Fix eslint-plugin/no-unused-message-ids lint issue

Author: FloEdelmann

lib/rules/block-tag-newline.js

@@ -72,8 +72,6 @@ module.exports = {
     messages: {
       unexpectedOpeningLinebreak:
         "There should be no line break after '<{{tag}}>'.",
-      unexpectedClosingLinebreak:
-        "There should be no line break before '</{{tag}}>'.",
       expectedOpeningLinebreak:
         "Expected {{expected}} after '<{{tag}}>', but {{actual}} found.",
       expectedClosingLinebreak: