Fix irregular whitespace (#2017)

Author: Shinigami92

lib/rules/no-required-prop-with-default.js

@@ -17,7 +17,7 @@ module.exports = {
     hasSuggestions: true,
     type: 'problem',
     docs: {
-      description: 'enforce props with default values ​​to be optional',
+      description: 'enforce props with default values to be optional',
       categories: undefined,
       url: 'https://eslint.vuejs.org/rules/no-required-prop-with-default.html'
     },