restrict partial word counting to names of reasoanble length

The partial word count does not split names to save a bit of time.
The result is that it might enounter unreasonably long names
which in truth consist of multiple words. No accurate statistics
are needed so simply restrict the count to words shorter than
75 characters.

nominatim/tokenizer/legacy_icu_tokenizer.py

@@ -163,7 +163,9 @@ class LegacyICUTokenizer:
             words = Counter()
             name_proc = ICUNameProcessor(self.naming_rules)
             with conn.cursor(name="words") as cur:
-                cur.execute("SELECT svals(name) as v, count(*) FROM place GROUP BY v")
+                cur.execute(""" SELECT v, count(*) FROM
+                                  (SELECT svals(name) as v FROM place)x
+                                WHERE length(v) < 75 GROUP BY v""")
 
                 for name, cnt in cur:
                     terms = set()