Fix some typos in comments

lib/liquid/block.rb

@@ -16,7 +16,7 @@ module Liquid
         when IsTag
           if token =~ FullToken
 
-            # if we found the proper block delimitor just end parsing here and let the outer block
+            # if we found the proper block delimiter just end parsing here and let the outer block
             # proceed
             if block_delimiter == $1
               end_tag
@@ -43,8 +43,8 @@ module Liquid
         end
       end
 
-      # Make sure that its ok to end parsing in the current block.
+      # Make sure that it's ok to end parsing in the current block.
-      # Effectively this method will throw and exception unless the current block is
+      # Effectively this method will throw an exception unless the current block is
       # of type Document
       assert_missing_delimitation!
     end

lib/liquid/document.rb

@@ -5,7 +5,7 @@ module Liquid
       parse(tokens)
     end
 
-    # There isn't a real delimter
+    # There isn't a real delimiter
     def block_delimiter
       []
     end

lib/liquid/file_system.rb

@@ -1,5 +1,5 @@
 module Liquid
-  # A Liquid file system is way to let your templates retrieve other templates for use with the include tag.
+  # A Liquid file system is a way to let your templates retrieve other templates for use with the include tag.
   #
   # You can implement subclasses that retrieve templates from the database, from the file system using a different
   # path structure, you can provide them as hard-coded inline strings, or any manner that you see fit.

lib/liquid/module_ex.rb

@@ -2,7 +2,7 @@
 # This library is free software. It may be used, redistributed and/or modified
 # under the same terms as Ruby itself
 #
-# This extension is usesd in order to expose the object of the implementing class
+# This extension is used in order to expose the object of the implementing class
 # to liquid as it were a Drop. It also limits the liquid-callable methods of the instance
 # to the allowed method passed with the liquid_methods call
 # Example:

lib/liquid/standardfilters.rb

@@ -11,12 +11,12 @@ module Liquid
       input.respond_to?(:size) ? input.size : 0
     end
 
-    # convert a input string to DOWNCASE
+    # convert an input string to DOWNCASE
     def downcase(input)
       input.to_s.downcase
     end
 
-    # convert a input string to UPCASE
+    # convert an input string to UPCASE
     def upcase(input)
       input.to_s.upcase
     end

lib/liquid/tag.rb

@@ -23,4 +23,4 @@ module Liquid
 
   end # Tag
 
-end # Tag
+end # Liquid