Fix crash introduced by removal of FrozenDict in 5613807, but without…

… constantly reallocating dicts

wpull/scraper/html.py

@@ -20,15 +20,23 @@
 _logger = StyleAdapter(logging.getLogger(__name__))
 
 
-LinkInfo = collections.namedtuple(
+_BaseLinkInfo = collections.namedtuple(
     'LinkInfoType',
     [
         'element', 'tag', 'attrib', 'link',
         'inline', 'linked', 'base_link', 'value_type',
         'link_type'
     ]
 )
-'''Information about a link in a lxml document.
+
+class LinkInfo(_BaseLinkInfo):
+    def __hash__(self):
+        return self.link.__hash__()
+
+    def __eq__(self, other):
+        return self.link.__eq__(other['link'])
+
+'''Information about a link in a lxml document.  Comparable on link only.
 
 Attributes:
     element: An instance of :class:`.document.HTMLReadElement`.