typo fix: remove duplicate period

Author: cczona

guides/source/asset_pipeline.md

@@ -42,7 +42,7 @@ The first feature of the pipeline is to concatenate assets. This is important in
 
 Rails 2.x introduced the ability to concatenate JavaScript and CSS assets by placing `:cache => true` at the end of the `javascript_include_tag` and `stylesheet_link_tag` methods. But this technique has some limitations. For example, it cannot generate the caches in advance, and it is not able to transparently include assets provided by third-party libraries.
 
-Starting with version 3.1, Rails defaults to concatenating all JavaScript files into one master `.js` file and all CSS files into one master `.css` file. As you'll learn later in this guide, you can customize this strategy to group files any way you like. In production, Rails inserts an MD5 fingerprint into each filename so that the file is cached by the web browser. You can invalidate the cache by altering this fingerprint, which happens automatically whenever you change the file contents..
+Starting with version 3.1, Rails defaults to concatenating all JavaScript files into one master `.js` file and all CSS files into one master `.css` file. As you'll learn later in this guide, you can customize this strategy to group files any way you like. In production, Rails inserts an MD5 fingerprint into each filename so that the file is cached by the web browser. You can invalidate the cache by altering this fingerprint, which happens automatically whenever you change the file contents.
 
 The second feature of the asset pipeline is asset minification or compression. For CSS files, this is done by removing whitespace and comments. For JavaScript, more complex processes can be applied. You can choose from a set of built in options or specify your own.