refactor into src-layout package.

test/test_wiki_diff_matcher.py

@@ -6,7 +6,7 @@ import pytest_asyncio
 from typing import List
 from deltas import Delete, Equal, Insert, wikitext_split
 from mwpersistence import Token
-from wiki_diff_matcher import WikiDiffMatcher
+from wikiq.wiki_diff_matcher import WikiDiffMatcher
 
 def _replace_whitespace(match):
     if match.group(1):  # If spaces matched (e.g., '  ')