mention that coercion only happens when the primary key is an integer…

… and use +to_i+ formatting

activerecord/lib/active_record/relation/finder_methods.rb

@@ -6,8 +6,8 @@ module FinderMethods
     # Find operates with four different retrieval approaches:
     #
     # * Find by id - This can either be a specific id (1), a list of ids (1, 5, 6), or an array of ids ([5, 6, 10]).
-    #   If no record can be found for all of the listed ids, then RecordNotFound will be raised. Find by id coerces
-    #   its arguments to integers using #to_i.
+    #   If no record can be found for all of the listed ids, then RecordNotFound will be raised. If the primary key
+    #   is an integer, find by id coerces its arguments using +to_i+.
     # * Find first - This will return the first record matched by the options used. These options can either be specific
     #   conditions or merely an order. If no record can be matched, +nil+ is returned. Use
     #   <tt>Model.find(:first, *args)</tt> or its shortcut <tt>Model.first(*args)</tt>.