Update plugins.md

Author: Benjamín Eidelman

docs/plugins.md

@@ -1,4 +1,4 @@
-```diff()```, ```patch()``` and ```reverse()``` functions are implemented using a pipes &filters pattern, making it extremely customizable by adding or replacing filters on a pipe.
+```diff()```, ```patch()``` and ```reverse()``` functions are implemented using a pipes &filters pattern, making them extremely customizable by adding or replacing filters.
 
 Some examples of what you can acheive writing your own filter:
 - diff special custom objects (eg. DOM nodes, native objects, functions, RegExp, node.js streams?)
@@ -7,4 +7,4 @@ Some examples of what you can acheive writing your own filter:
 - implement custom diff mechanisms, like relative numeric deltas
 - suprise me! :)
 
-Check the ```/src/filters``` folder for more example code.
+Check the ```/src/filters``` folder for more example code.