RFR: XXXS fix 1-char typo in doc comment; JDK-8213820: unknown tag: @returns

[Jonathan Gibbons]

Please review this trivial fix for an incorrectly spelt tag name in 
public documentation.

$ hg diff -R open
diff -r bbbcd90f0adb 
src/java.base/share/classes/java/lang/ref/Reference.java
--- a/src/java.base/share/classes/java/lang/ref/Reference.java  Tue Nov 
13 16:49:58 2018 -0500
+++ b/src/java.base/share/classes/java/lang/ref/Reference.java  Tue Nov 
13 16:03:21 2018 -0800
@@ -379,7 +379,7 @@
       * Throws {@link CloneNotSupportedException}. A {@code Reference} 
cannot be
       * meaningfully cloned. Construct a new {@code Reference} instead.
       *
-     * @returns never returns normally
+     * @return never returns normally
       * @throws  CloneNotSupportedException always
       *
       * @since 11

(Separately, there are a depressing number of "@params" and even a 
"@returnss" in comments for private members or internal classes!)

-- Jon

JBS: https://bugs.openjdk.java.net/browse/JDK-8213820