Clarify last change.

doc/emacs/building.texi

@@ -1253,11 +1253,11 @@ recompile it until they think it is ready to use.
 @vindex load-path
   The variable @code{load-path} specifies the sequence of directories
 searched by @kbd{M-x load-library}.  Its value should be a list of
-strings that are directory names, or @code{nil} for the current
-default directory.  (Generally, it is not a good idea to put
-@code{nil} in the list; if you find yourself wishing that @code{nil}
-were in the list, most likely what you really want is to do @kbd{M-x
-load-file} this once.)
+strings that are directory names; in addition, @code{nil} in this list
+stands for the current default directory.  (Generally, it is not a
+good idea to put @code{nil} in the list; if you find yourself wishing
+that @code{nil} were in the list, most likely what you really want is
+to do @kbd{M-x load-file} this once.)
 
   The default value of @code{load-path} is a list of directories where
 the Lisp code for Emacs itself is stored.  If you have libraries of