Tiny documentation edits [ci skip]

activerecord/lib/active_record/associations.rb

@@ -1019,7 +1019,7 @@ def association_instance_set(name, association)
     # can affect what it does.
     #
     # Note that <tt>:dependent</tt> option is ignored for +has_one+ <tt>:through</tt> associations.
-    # 
+    #
     # === Delete or destroy?
     #
     # +has_many+ and +has_and_belongs_to_many+ associations have the methods <tt>destroy</tt>,
@@ -1529,8 +1529,6 @@ def has_one(name, scope = nil, options = {})
       #   NOTE: <tt>required</tt> is set to <tt>true</tt> by default and is deprecated. If
       #   you don't want to have association presence validated, use <tt>optional: true</tt>.
       #
-      #
-      #
       # Option examples:
       #   belongs_to :firm, foreign_key: "client_of"
       #   belongs_to :person, primary_key: "name", foreign_key: "person_name"

activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb

@@ -770,7 +770,7 @@ def remove_foreign_key(from_table, options_or_to_table = {})
       #   # Check a foreign key exists
       #   foreign_key_exists?(:accounts, :branches)
       #
-      #   # Check a foreign key on specified column exists
+      #   # Check a foreign key on a specified column exists
       #   foreign_key_exists?(:accounts, column: :owner_id)
       #
       #   # Check a foreign key with a custom name exists

guides/source/association_basics.md

@@ -959,7 +959,8 @@ If you set the `:validate` option to `true`, then associated objects will be val
 
 ##### `:optional`
 
-If you set the `:optional` option to `true`, then associated object will be validated for presence. By default, this is `false`: associated objects will be validated for presence.
+If you set the `:optional` option to `true`, then the presence of the associated
+object won't be validated. By default, this option is set to `false`.
 
 #### Scopes for `belongs_to`