8211449: Correction to the spec of implicit negative subpattern in DecimalFormat

Reviewed-by: bpb

Author: naotoj

src/java.base/share/classes/java/text/DecimalFormat.java

@@ -127,7 +127,7 @@
  * subpattern, for example, {@code "#,##0.00;(#,##0.00)"}.  Each
  * subpattern has a prefix, numeric part, and suffix. The negative subpattern
  * is optional; if absent, then the positive subpattern prefixed with the
- * localized minus sign ({@code '-'} in most locales) is used as the
+ * minus sign ({@code '-' U+002D HYPHEN-MINUS}) is used as the
  * negative subpattern. That is, {@code "0.00"} alone is equivalent to
  * {@code "0.00;-0.00"}.  If there is an explicit negative subpattern, it
  * serves only to specify the negative prefix and suffix; the number of digits,