Restore README to some distribution pages

Now that PGXN::API indexes READMEs as extension documentation when
the metadata points to it or there is no other documentation, cease
removing the README from the list of documentation to show. This allows
the README to continue to appear on the distributio home page, as for
https://pgxn.org/dist/pg_later/. Resolves #17.

Changes

@@ -1,6 +1,8 @@
 Revision history for Perl extension PGXN::Site
 
 0.23.5
+      - Restored the README to releases where the README is also listed as
+        extension documentation (#17).
 
 0.23.4  2024-02-06T23:47:18Z
       - Fixed the dependency configuration in `Build.PL` so it actually knows

lib/PGXN/Site/Templates.pm

@@ -560,7 +560,8 @@ template distribution => sub {
                         my $path = $info->{docpath};
                         dt {
                             if ($path) {
-                                delete $docs->{$path};
+                                # Exclude from doc list except for root readme.
+                                delete $docs->{$path} unless $path eq 'README';
                                 a {
                                     href is $req->uri->path . "$sep$path.html";
                                     span { class is 'fn';       $ext             };