Merge pull request #17828 from yui-knk/fix/i18n_guide

[ci skip] fix class name

guides/source/i18n.md

@@ -626,7 +626,7 @@ entry[count == 1 ? 0 : 1]
 
 I.e. the translation denoted as `:one` is regarded as singular, the other is used as plural (including the count being zero).
 
-If the lookup for the key does not return a Hash suitable for pluralization, an `18n::InvalidPluralizationData` exception is raised.
+If the lookup for the key does not return a Hash suitable for pluralization, an `I18n::InvalidPluralizationData` exception is raised.
 
 ### Setting and Passing a Locale