Update ICU to 58.1

source/i18n/unicode/uformattable.h

Index: source/i18n/unicode/uformattable.h
diff --git a/source/i18n/unicode/uformattable.h b/source/i18n/unicode/uformattable.h
index a64ae14653a19d56a86e6a1a4967d3518b213a99..e4683d56c358987b0a8bd5b404c53b1cfb71004d 100644
--- a/source/i18n/unicode/uformattable.h
+++ b/source/i18n/unicode/uformattable.h
@@ -1,3 +1,5 @@
+// Copyright (C) 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
 /*
 ********************************************************************************
 * Copyright (C) 2013-2014, International Business Machines Corporation and others.
@@ -49,7 +51,13 @@ typedef enum UFormattableType {
   UFMT_ARRAY,    /**< ufmt_countArray() and ufmt_getArray() will return the value.  @see ufmt_getArrayItemByIndex */
   UFMT_INT64,    /**< ufmt_getInt64() will return without conversion. @see ufmt_getInt64 */
   UFMT_OBJECT,   /**< ufmt_getObject() will return without conversion.  @see ufmt_getObject*/
-  UFMT_COUNT     /**< Count of defined UFormattableType values */
+#ifndef U_HIDE_DEPRECATED_API
+    /**
+     * One more than the highest normal UFormattableType value.
+     * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
+     */
+    UFMT_COUNT
+#endif  // U_HIDE_DEPRECATED_API
 } UFormattableType;