Change uniq validation with conditions examples to use where with hashes

Take the opportunity to showcase where.not.

activerecord/lib/active_record/validations/uniqueness.rb

@@ -4,7 +4,7 @@ class UniquenessValidator < ActiveModel::EachValidator # :nodoc:
       def initialize(options)
         if options[:conditions] && !options[:conditions].respond_to?(:call)
           raise ArgumentError, "#{options[:conditions]} was passed as :conditions but is not callable. " \
-                               "Pass a callable instead: `conditions: -> { where('approved = ?', true) }`"
+                               "Pass a callable instead: `conditions: -> { where(approved: true) }`"
         end
         super({ case_sensitive: true }.merge!(options))
       end
@@ -120,7 +120,7 @@ module ClassMethods
       # of the title attribute:
       #
       #   class Article < ActiveRecord::Base
-      #     validates_uniqueness_of :title, conditions: -> { where('status != ?', 'archived') }
+      #     validates_uniqueness_of :title, conditions: -> { where.not(status: 'archived') }
       #   end
       #
       # When the record is created, a check is performed to make sure that no
@@ -136,7 +136,7 @@ module ClassMethods
       #   the uniqueness constraint.
       # * <tt>:conditions</tt> - Specify the conditions to be included as a
       #   <tt>WHERE</tt> SQL fragment to limit the uniqueness constraint lookup
-      #   (e.g. <tt>conditions: -> { where('status = ?', 'active') }</tt>).
+      #   (e.g. <tt>conditions: -> { where(status: 'active') }</tt>).
       # * <tt>:case_sensitive</tt> - Looks for an exact match. Ignored by
       #   non-text columns (+true+ by default).
       # * <tt>:allow_nil</tt> - If set to +true+, skips this validation if the

activerecord/test/cases/validations/uniqueness_validation_test.rb

@@ -348,7 +348,7 @@ def test_validate_straight_inheritance_uniqueness
   end
 
   def test_validate_uniqueness_with_conditions
-    Topic.validates_uniqueness_of :title, conditions: -> { where('approved = ?', true) }
+    Topic.validates_uniqueness_of :title, conditions: -> { where(approved: true) }
     Topic.create("title" => "I'm a topic", "approved" => true)
     Topic.create("title" => "I'm an unapproved topic", "approved" => false)
 
@@ -361,7 +361,7 @@ def test_validate_uniqueness_with_conditions
 
   def test_validate_uniqueness_with_non_callable_conditions_is_not_supported
     assert_raises(ArgumentError) {
-      Topic.validates_uniqueness_of :title, conditions: Topic.where('approved = ?', true)
+      Topic.validates_uniqueness_of :title, conditions: Topic.where(approved: true)
     }
   end