update contribute.html for regression testing

[Robert Lipe]

We've had a "gentelmen's agreement" on this subject for a long time, but
we seem to have not written the rules down.  Here's a start.

Index: contribute.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/contribute.html,v
retrieving revision 1.29
diff -c -5 -p -u -r1.29 contribute.html
cvs server: conflicting specifications of output style
--- contribute.html     2000/11/05 09:36:52     1.29
+++ contribute.html     2000/11/07 15:53:15
@@ -52,10 +52,14 @@ on file.</p>
   <li> A ChangeLog entry as plaintext; see the various ChangeLog files
        for format and content.<br>
        Note that, unlike some other projects, we do require ChangeLogs
        also for documentation (i.e., .texi files).  They are not required
        for updates to the web pages.
+  <li> A list of targets where the patch survived a bootstrap of GCC.  A
+       bootstrap on least one host is required for any non-trivial change.
+  <li> A list of targets where the GCC testsuite was run, including an 
+       analysis of any regressions.
   <li> <p>The patch itself.  If you are accessing the <a href="cvs.html">
        CVS repository</a> at gcc.gnu.org, use 
        "<code>cvs update; cvs diff -c3p</code>"; else, use 
        "<code>diff -c3p OLD NEW</code>" or 
        "<code>diff -up OLD NEW</code>".