docs/parse-support-md: Allow definition lists for features

Now, as well as a `code block', with
  |    Something: some status
we tolerate a definition list which in pandoc terms looks like this
  |Term
  |: Definition

This ought not usually be be used for features but it will be useful
for linking to the release notes, because markup is not allowed in
code blocks but is in definitions.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Juergen Gross <jgross@suse.com>

docs/parse-support-md

@@ -191,6 +191,33 @@ sub ri_CodeBlock {
     }
 }
 
+sub ri_DefinitionList {
+    my ($c) = @_;
+    foreach my $defent (@$c) {
+        my ($term, $defns) = @$defent;
+        my $descr =
+            join ' ',
+            map { $_->{c} }
+            grep { $_->{t} eq 'Str' }
+            @$term;
+        push @insections,
+            {
+             Key => descr2key($descr),
+             Headline => $term,
+            };
+        die "multiple definitions in definition list definition"
+            if @$defns > 1;
+        my $defn = $defns->[0];
+        die "multiple paras in definition list definition"
+            if @$defn > 1;
+        my $defnp = $defn->[0];
+        die "only understand plain definition not $defnp->{t} ?"
+            unless $defnp->{t} eq 'Plain';
+        parse_feature_entry $defnp->{c};
+        pop @insections;
+    }
+}
+
 sub process_unknown {
     my ($c, $e) = @_;
     $had_unknown = Dumper($e);