Description:
------------
The function reference links look like:

http://php.net/manual/en/function.array-filter.php

That *.php in the end is annoying when I'm directly editing the link to navigate 
quickly to a known function.

And, implementing a bonus rewrite rule is not that hard.

So, we could end up with links, like:

http://php.net/manual/en/function/array_filter

That perfectly reflects the function name, and is a breeze to navigate to 
different function.

Test script:
---------------
Open the URL: http://php.net/manual/en/function/array_filter

Expected result:
----------------
Open up (not redirect) the same page that resides under 
http://php.net/manual/en/function.array-filter.php

Actual result:
--------------
The manual page you are looking for 
(http://php.net/manual/en/function/array_filter) is not available on this server 
right now. Please check back later, or if the problem persist, contact the 
webmasters.