Apply Layout/LineLength rubocop rule

Note we're excluding a few files:

* Configuration files that weren't generated by us
* Migration files that weren't generated by us
* The Gemfile, since it includes an important comment that must be on
  the same line as the gem declaration
* The Budget::Stats class, since the heading statistics are a mess and
  having shorter lines would require a lot of refactoring

app/models/verification/management/email.rb

@@ -53,10 +53,12 @@ class Verification::Management::Email
       return if errors.count > 0
 
       if document_number_mismatch?
-        errors.add(:email,
-                   I18n.t("management.email_verifications.document_mismatch",
-                          document_type: ApplicationController.helpers.humanize_document_type(user.document_type),
-                          document_number: user.document_number))
+        errors.add(
+          :email,
+          I18n.t("management.email_verifications.document_mismatch",
+                 document_type: ApplicationController.helpers.humanize_document_type(user.document_type),
+                 document_number: user.document_number)
+        )
       end
     end