Correct validators so that existing error messages would look correct (#3668)

app/validators/blacklisted_email_validator.rb

@@ -1,8 +1,8 @@
 # frozen_string_literal: true
 
-class EmailValidator < ActiveModel::EachValidator
-  def validate_each(record, attribute, value)
-    record.errors.add(attribute, I18n.t('users.invalid_email')) if blocked_email?(value)
+class BlacklistedEmailValidator < ActiveModel::Validator
+  def validate(user)
+    user.errors.add(:email, I18n.t('users.invalid_email')) if blocked_email?(user.email)
   end
 
   private
@@ -15,7 +15,7 @@ class EmailValidator < ActiveModel::EachValidator
     return false if Rails.configuration.x.email_domains_blacklist.blank?
 
     domains = Rails.configuration.x.email_domains_blacklist.gsub('.', '\.')
-    regexp = Regexp.new("@(.+\\.)?(#{domains})", true)
+    regexp  = Regexp.new("@(.+\\.)?(#{domains})", true)
 
     value =~ regexp
   end
@@ -24,7 +24,7 @@ class EmailValidator < ActiveModel::EachValidator
     return false if Rails.configuration.x.email_domains_whitelist.blank?
 
     domains = Rails.configuration.x.email_domains_whitelist.gsub('.', '\.')
-    regexp = Regexp.new("@(.+\\.)?(#{domains})$", true)
+    regexp  = Regexp.new("@(.+\\.)?(#{domains})$", true)
 
     value !~ regexp
   end

app/validators/unreserved_username_validator.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class UnreservedUsernameValidator < ActiveModel::Validator
+  def validate(account)
+    return if account.username.nil?
+    account.errors.add(:username, I18n.t('accounts.reserved_username')) if reserved_username?(account.username)
+  end
+
+  private
+
+  def reserved_username?(value)
+    return false unless Setting.reserved_usernames
+    Setting.reserved_usernames.include?(value.downcase)
+  end
+end

app/validators/unreserved_validator.rb

@@ -1,15 +0,0 @@
-# frozen_string_literal: true
-
-class UnreservedValidator < ActiveModel::EachValidator
-  def validate_each(record, attribute, value)
-    return if value.nil?
-    record.errors.add(attribute, I18n.t('accounts.reserved_username')) if reserved_username?(value)
-  end
-
-  private
-
-  def reserved_username?(value)
-    return false unless Setting.reserved_usernames
-    Setting.reserved_usernames.include?(value.downcase)
-  end
-end