[ci skip] Small grammar fix

actionview/lib/action_view/helpers/date_helper.rb

@@ -226,7 +226,7 @@ def time_ago_in_words(from_time, options = {})
       #   for <tt>:year</tt>, <tt>:month</tt>, <tt>:day</tt>, <tt>:hour</tt>, <tt>:minute</tt> and <tt>:second</tt>.
       #   Setting this option prepends a select option with a generic prompt  (Day, Month, Year, Hour, Minute, Seconds)
       #   or the given prompt string.
-      # * <tt>:with_css_classes</tt>  - Set to true or a hash of strings. Use true if you want assign generic styles for
+      # * <tt>:with_css_classes</tt>  - Set to true or a hash of strings. Use true if you want to assign generic styles for
       #   select tags. This automatically set classes 'year', 'month', 'day', 'hour', 'minute' and 'second'. A hash of
       #   strings for <tt>:year</tt>, <tt>:month</tt>, <tt>:day</tt>, <tt>:hour</tt>, <tt>:minute</tt>, <tt>:second</tt>
       #   will extend the select type with the given value. Use +html_options+ to modify every select tag in the set.