Fix attribute annotation code for FACEs

This fixes several related issues:

* `<span>form-associated custom elements</span>` was not matching the
  regex that was looking for `<code>` in the attribute index.
* Changing the regex to look for span or code causes many other lines to
  be picked up. Thus, we introduce the new 'tr' state into the state
  machine to better detect the first line of a <tr>.
* Even with that, we were now dying on global attributes, since they
  don't have a domintro to get substituted in to. So we remove that
  error state.
* Finally, we were now substituting in even in cases that just mention
  the attribute, like "Global attributes, except the is attribute". So,
  we need to add an escape hatch for that.

Author: domenic

.pre-process-annotate-attributes.pl

@@ -30,20 +30,28 @@
                 if (not exists $instances{$key}) {
                     $instances{$key} = [];
                 }
-                push(@{$instances{$key}}, { line => $line, special => $special });
+                if ($notes !~ m@<!-- no-annotate -->@os) {
+                    push(@{$instances{$key}}, { line => $line, special => $special });
+                }
             } elsif ($_ =~ m/^   <!--.*-->\n$/os) {
                 # ignore
             } elsif ($_ eq "   <dd>Any other attribute that has no namespace (see prose).</dd>\n") {
                 # ignore
             } elsif ($_ =~ m!^   <dt>!o) {
                 $mode = 'bored';
             } else {
-                die "mode=$mode saw: $_";
+                # ignore
             }
         } elsif ($mode eq 'index') {
             if ($_ eq "  </table>\n") {
-               $mode = 'end';
-            } elsif ($_ =~ m!^     <td> <code data-x="([^"]+)">[^<]*</code>;?\n$!os) {
+                $mode = 'end';
+            } elsif ($_ eq "    <tr>\n") {
+                $mode = 'tr';
+            } else {
+                # ignore...
+            }
+        } elsif ($mode eq 'tr') {
+            if ($_ =~ m!^     <td> <(?:code|span) data-x="([^"]+)">[^<]*</(?:code|span)>;?\n$!os) {
                 $attributes{$1} = 1;
                 $mode = 'index-in';
             } else {
@@ -57,7 +65,6 @@
                 my $description = $1;
                 my $altdescription = $2;
                 foreach my $key (keys %attributes) {
-                    die "can't find instance of $key\n" unless exists $instances{$key} and scalar @{$instances{$key}};
                     foreach my $entry (@{$instances{$key}}) {
                         my $line = $entry->{line};
                         if ($entry->{special} eq 'global') {