Fix typo [ci skip]

actionmailer/lib/action_mailer/preview.rb

@@ -20,7 +20,7 @@ module ActionMailer
         interceptors.flatten.compact.each { |interceptor| register_preview_interceptor(interceptor) }
       end
 
-      # Register am Interceptor which will be called before mail is previewed.
+      # Register an Interceptor which will be called before mail is previewed.
       # Either a class or a string can be passed in as the Interceptor. If a
       # string is passed in it will be <tt>constantize</tt>d.
       def register_preview_interceptor(interceptor)

activerecord/CHANGELOG.md

@@ -763,7 +763,7 @@
 *   Raise `ActiveRecord::RecordNotDestroyed` when a replaced child
     marked with `dependent: destroy` fails to be destroyed.
 
-    Fixex #12812.
+    Fixes #12812.
 
     *Brian Thomas Storti*