Fix incorrect help anchors with special characters

The collector regex removed all non alphanumerical characters which
worked fine if there was also a space next to them, as in the next step
it converted one or more spaces to dash.

If however this extra character such as a : was directly embedded in the
word this produced a different result compared to how markdown works.

Now we replace all special characters with space, and space gets
replaced with dash

Author: dutow

app/controllers/help_controller.rb

@@ -39,7 +39,7 @@ def extract_outline(text)
       if line =~ /^(\#{2,3})\s+(.+)$/
         level = $1.length
         title = $2.strip
-        id = title.downcase.gsub(/[^a-z0-9\s-]/, "").gsub(/\s+/, "-")
+        id = title.downcase.gsub(/[^a-z0-9\s-]/, " ").gsub(/\s+/, "-")
         headings << { level: level, title: title, id: id }
       end
     end