Update null storage description.

Author: bmomjian

doc/FAQ

@@ -1,7 +1,7 @@
 
                 Frequently Asked Questions (FAQ) for PostgreSQL
 
-   Last updated: Fri Jan 23 09:41:43 EST 2004
+   Last updated: Sat Jan 24 21:28:41 EST 2004
 
    Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
 
@@ -737,7 +737,7 @@
    Indexes do not require as much overhead, but do contain the data that
    is being indexed, so they can be large also.
 
-   NULLs are stored in bitmaps, so they use very little space.
+   NULLs are stored as bitmaps, so they use very little space.
 
     4.7) How do I find out what tables, indexes, databases, and users are
     defined?

doc/src/FAQ/FAQ.html

@@ -10,7 +10,7 @@
   alink="#0000ff">
     <H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
 
-    <P>Last updated: Fri Jan 23 09:41:43 EST 2004</P>
+    <P>Last updated: Sat Jan 24 21:28:41 EST 2004</P>
 
     <P>Current maintainer: Bruce Momjian (<A href=
     "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
@@ -928,7 +928,7 @@ <H4><A name="4.6">4.6</A>) How much database disk space is required
     <P>Indexes do not require as much overhead, but do contain the data
     that is being indexed, so they can be large also.</P>
 
-    <P><SMALL>NULL</SMALL>s are stored in bitmaps, so they
+    <P><SMALL>NULL</SMALL>s are stored as bitmaps, so they
     use very little space.</P>
 
     <H4><A name="4.7">4.7</A>) How do I find out what tables, indexes,