add sanitizer for TIGER tags

Currently only takes over cleaning the tiger:county data. This was
done by the import until now.

nominatim/tokenizer/sanitizers/clean_tiger_tags.py

@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2022 by the Nominatim developer community.
+# For a full list of authors see the git log.
+"""
+Sanitizer that preprocesses tags from the TIGER import.
+
+It makes the following changes:
+
+* remove state reference from tiger:county
+"""
+from typing import Callable
+import re
+
+from nominatim.tokenizer.sanitizers.base import ProcessInfo
+from nominatim.tokenizer.sanitizers.config import SanitizerConfig
+
+COUNTY_MATCH = re.compile('(.*), [A-Z][A-Z]')
+
+def _clean_tiger_county(obj: ProcessInfo) -> None:
+    """ Remove the state reference from tiger:county tags.
+
+        This transforms a name like 'Hamilton, AL' into 'Hamilton'.
+        If no state reference is detected at the end, the name is left as is.
+    """
+    if not obj.address:
+        return
+
+    for item in obj.address:
+        if item.kind == 'tiger' and item.suffix == 'county':
+            m = COUNTY_MATCH.fullmatch(item.name)
+            if m:
+                item.name = m[1]
+            # Switch kind and suffix, the split left them reversed.
+            item.kind = 'county'
+            item.suffix = 'tiger'
+
+            return
+
+
+def create(_: SanitizerConfig) -> Callable[[ProcessInfo], None]:
+    """ Create a housenumber processing function.
+    """
+    return _clean_tiger_county