minor: adding link target

Author: Sam Kleinman

source/faq/developers.txt

@@ -151,8 +151,10 @@ flag to modify the file preallocation strategy.
 
 .. seealso:: This wiki page that address :wiki:`MongoDB disk use <Excessive+Disk+Space>`.
 
-How do I optimize storage for small documents?
-----------------------------------------------
+.. _faq-small-documents:
+
+How do I optimize storage use for small documents?
+--------------------------------------------------
 
 Each MongoDB document contains a certain amount of overhead. This
 overhead is normally insignificant but becomes significant if all