tld: fix assigning a dict to an attribute originally defined as a list

New type-hinted parser attribute to store the parsed data instead, and
delete the temporary value used during parsing.

Said new type hint isn't doing much work yet since the code that
eventually assigns to the new attribute isn't hinted, but I don't want
to change too much in this particular branch; we're ONLY worried about
actual mypy errors right now. Hinting more stuff for real comes later.

sopel/modules/tld.py

@@ -13,6 +13,7 @@
 from html.parser import HTMLParser
 import logging
 import re
+from typing import Dict
 
 import pytz
 import requests
@@ -100,6 +101,7 @@ def __init__(self):
         self.current_cell = ''
         self.rows = []
         self.tables = []
+        self.parsed: Dict[str, Dict[str, str]] = {}
         self.finished = False
 
     def handle_starttag(self, tag, attrs):
@@ -158,7 +160,7 @@ def get_processed_data(self):
         LOGGER.debug("Processed TLD data requested.")
         if self.finished:
             LOGGER.debug("Returning stored previously-processed data.")
-            return self.tables
+            return self.parsed
 
         LOGGER.debug("Ensuring all buffered data has been parsed.")
         self.close()
@@ -202,8 +204,12 @@ def get_processed_data(self):
                     tld_list[idn_key] = zipped
 
         LOGGER.debug("Finished processing TLD data; returning it.")
-        self.tables = tld_list
         self.finished = True
+        # clear working data
+        del self.tables
+        # cache parsed data for future requests to this parser
+        self.parsed = tld_list
+
         return self.tables