[ci skip] Improve doc, fix grammatical issue

activerecord/lib/active_record/nested_attributes.rb

@@ -485,10 +485,10 @@ module ActiveRecord
     end
 
     # Takes in a limit and checks if the attributes_collection has too many
-    # records. The method will take limits in the form of symbols, procs, and
-    # number-like objects (anything that can be compared with an integer).
+    # records. It accepts limit in the form of symbol, proc, or
+    # number-like object (anything that can be compared with an integer).
     #
-    # Will raise an TooManyRecords error if the attributes_collection is
+    # Raises TooManyRecords error if the attributes_collection is
     # larger than the limit.
     def check_record_limit!(limit, attributes_collection)
       if limit
@@ -519,7 +519,7 @@ module ActiveRecord
       ConnectionAdapters::Column.value_to_boolean(hash['_destroy'])
     end
 
-    # Determines if a new record should be build by checking for
+    # Determines if a new record should be rejected by checking
     # has_destroy_flag? or if a <tt>:reject_if</tt> proc exists for this
     # association and evaluates to +true+.
     def reject_new_record?(association_name, attributes)

guides/source/nested_model_forms.md

@@ -17,9 +17,9 @@ Model setup
 
 To be able to use the nested model functionality in your forms, the model will need to support some basic operations.
 
-First of all, it needs to define a writer method for the attribute that corresponds to the association you are building a nested model form for. The `fields_for` form helper will look for this method to decide whether or not a nested model form should be build.
+First of all, it needs to define a writer method for the attribute that corresponds to the association you are building a nested model form for. The `fields_for` form helper will look for this method to decide whether or not a nested model form should be built.
 
-If the associated object is an array a form builder will be yielded for each object, else only a single form builder will be yielded.
+If the associated object is an array, a form builder will be yielded for each object, else only a single form builder will be yielded.
 
 Consider a Person model with an associated Address. When asked to yield a nested FormBuilder for the `:address` attribute, the `fields_for` form helper will look for a method on the Person instance named `address_attributes=`.
 
@@ -220,6 +220,6 @@ As you can see it has generated 2 `project name` inputs, one for each new `proje
 
 You can basically see the `projects_attributes` hash as an array of attribute hashes, one for each model instance.
 
-NOTE: The reason that `fields_for` constructed a form which would result in a hash instead of an array is that it won't work for any forms nested deeper than one level deep.
+NOTE: The reason that `fields_for` constructed a hash instead of an array is that it won't work for any form nested deeper than one level deep.
 
 TIP: You _can_ however pass an array to the writer method generated by `accepts_nested_attributes_for` if you're using plain Ruby or some other API access. See (TODO) for more info and example.