use addr+place subfield for Taiwan

this assumes that the address format included both fields as a "hacky" workaround of iD's inability to choose between streets and places from a single field. This is (at the momemt) only based on the observation that before the format was introduced in iD in mid-2016, there were only a very small number of addresses in Taiwan with both tags, and the number increased only after iD started to show fields for both tags, and even today only a very small percentage of addresses have both tags set (approx 2.1k out of 1.6M).

data/address_formats.json

@@ -112,7 +112,7 @@
     "countryCodes": ["tw"],
     "format": [
       ["postcode", "city", "district"],
-      ["place", "street"],
+      ["street+place"],
       ["housenumber", "floor", "unit"]
     ]
   },