Merge pull request #10160 from choudhuryanupam/fix_typo_n_grammar

Fixed typo

activesupport/test/caching_test.rb

@@ -405,7 +405,7 @@ def test_really_long_keys
 end
 
 # https://rails.lighthouseapp.com/projects/8994/tickets/6225-memcachestore-cant-deal-with-umlauts-and-special-characters
-# The error is caused by charcter encodings that can't be compared with ASCII-8BIT regular expressions and by special
+# The error is caused by character encodings that can't be compared with ASCII-8BIT regular expressions and by special
 # characters like the umlaut in UTF-8.
 module EncodedKeyCacheBehavior
   Encoding.list.each do |encoding|