Fix issue in Marionette scraper

Fixes #532.

lib/docs/filters/marionette/clean_html.rb

@@ -12,7 +12,11 @@ module Docs
       end
 
       def other
-        css('#source + h2', '#improve', '#source', '.glyphicon', 'p > br').remove
+        css('#source + h2', '#improve', '#source', '.glyphicon').remove
+
+        css('p > br').each do |node|
+          node.replace(' ')
+        end
 
         css('pre > code').each do |node|
           node.parent['data-language'] = node['class'][/lang-(\w+)/, 1] if node['class']