Moved "`mod_expires` to be enabled" to new line.

- Right now the comment was not rendering properly.
  # The Expires* directives requires the Apache module
  `mod_expires` to be
  # enabled.
- After this change -
  # The Expires* directives requires the Apache module
  # `mod_expires` to be enabled.

guides/source/asset_pipeline.md

@@ -760,8 +760,8 @@ headers.
 For Apache:
 
 ```apache
-# The Expires* directives requires the Apache module `mod_expires` to be
-# enabled.
+# The Expires* directives requires the Apache module
+# `mod_expires` to be enabled.
 <Location /assets/>
   # Use of ETag is discouraged when Last-Modified is present
   Header unset ETag FileETag None