add exception type and documentation for when rate limiting exception

(but not any tests, because that is kind of hard to test without possibly causing a DOS)

libs/core/src/main/java/de/westnordost/osmapi/OsmApiErrorFactory.java

@@ -2,14 +2,7 @@
 
 import java.net.HttpURLConnection;
 
-import de.westnordost.osmapi.common.errors.OsmApiException;
-import de.westnordost.osmapi.common.errors.OsmAuthorizationException;
-import de.westnordost.osmapi.common.errors.OsmBadUserInputException;
-import de.westnordost.osmapi.common.errors.OsmConflictException;
-import de.westnordost.osmapi.common.errors.OsmConnectionException;
-import de.westnordost.osmapi.common.errors.OsmNotFoundException;
-import de.westnordost.osmapi.common.errors.OsmPreconditionFailedException;
-import de.westnordost.osmapi.common.errors.OsmServiceUnavailableException;
+import de.westnordost.osmapi.common.errors.*;
 
 /** Static factory that creates the OsmApiExceptions from the HTTP response code and message */
 public class OsmApiErrorFactory
@@ -38,6 +31,8 @@ public static RuntimeException createError(int error, String response, String de
 				return new OsmConflictException(error, response, description);
 			case HttpURLConnection.HTTP_BAD_REQUEST:
 				return new OsmBadUserInputException(error, response, description);
+			case 429:
+				return new OsmTooManyRequestsException(error, response, description);
 
 			default:
 				return createGenericError(error, response, description);

libs/core/src/main/java/de/westnordost/osmapi/common/errors/OsmTooManyRequestsException.java

@@ -0,0 +1,11 @@
+package de.westnordost.osmapi.common.errors;
+
+/** When the request has been blocked due to rate limiting */
+public class OsmTooManyRequestsException extends OsmApiException {
+    private static final long serialVersionUID = 1L;
+
+    public OsmTooManyRequestsException(int errorCode, String errorTitle, String description)
+    {
+        super(errorCode, errorTitle, description);
+    }
+}

libs/map/src/main/java/de/westnordost/osmapi/map/MapDataApi.java

@@ -114,6 +114,7 @@ public long updateMap(Map<String, String> tags, Iterable<Element> elements,
 	 *                                   map (Permission.MODIFY_MAP)
 	 * @throws OsmPreconditionFailedException if the deletion of an element was uploaded but that
 	 *                                        element is still referred to by another element
+	 * @throws OsmTooManyRequestsException if the request has been blocked due to rate limiting
 	 *  */
 	public void uploadChanges(long changesetId, Iterable<Element> elements, Handler<DiffElement> handler)
 	{