Added descripton for box shadow mixin and updated box-shadow sass file so it gets parsed through markdown correctly

doc-src/content/reference/compass/css3/box_shadow.haml

@@ -8,4 +8,4 @@ classnames:
 ---
 - render 'reference' do
   %p
-    Lorem ipsum dolor sit amet.
+    The box-shadow mixin is used to give a block element a drop shadow.

frameworks/compass/stylesheets/compass/css3/_box_shadow.sass

@@ -1,10 +1,12 @@
-//**
-  Provides cross-browser css box shadows for Webkit, Gecko, and CSS3 standard
-  arguments are color, horizontal offset, vertical offset, and blur
+//
+  Provides cross-browser css box shadows for Webkit, Gecko, and CSS3.
 
-//**
+  Standard arguments are color, horizontal offset, vertical offset, and blur.
+
+//
   These defaults make the arguments optional for this mixin
-  If you like, set different defaults in your project
+
+  If you like, set different defaults in your project.
   
 !default_box_shadow_color     ||= #333
 !default_box_shadow_h_offset  ||= 1px