Added an "Alt..." details just below attachments with them.

The alt text is still also generated as 'alt' and 'name' attributes,
but this is more usable from phones and tablets.

activitypub.c

@@ -239,7 +239,7 @@ xs_list *get_attachments(const xs_dict *msg)
             if (xs_is_null(name))
                 name = xs_dict_get(msg, "name");
             if (xs_is_null(name))
-                name = L("No description");
+                name = "";
 
             xs *d = xs_dict_new();
             d = xs_dict_append(d, "type", type);

html.c

@@ -1891,6 +1891,9 @@ xs_html *html_entry(snac *user, xs_dict *msg, int read_only,
                         xs_html_tag("a",
                             xs_html_attr("href", href),
                             xs_html_text(href))));
+
+                /* do not generate an Alt... */
+                name = NULL;
             }
             else {
                 xs_html_add(content_attachments,
@@ -1900,6 +1903,18 @@ xs_html *html_entry(snac *user, xs_dict *msg, int read_only,
                             xs_html_text(L("Attachment")),
                             xs_html_text(": "),
                             xs_html_text(href))));
+
+                /* do not generate an Alt... */
+                name = NULL;
+            }
+
+            if (name != NULL && *name) {
+                xs_html_add(content_attachments,
+                    xs_html_tag("p",
+                        xs_html_tag("details",
+                            xs_html_tag("summary",
+                                xs_html_text(L("Alt..."))),
+                            xs_html_text(name))));
             }
         }
     }