RFR 8159713 and 8161183 : minor fixes for jar.properties

[Leo Jiang]

Please review the minor changes in jar.properties file for L10n issue.

CR: 
http://cr.openjdk.java.net/~fyuan/leo/8159713-8161183/webrev.00/src/jdk.jartool/share/classes/sun/tools/jar/resources/jar.properties.udiff.html

We have two issues related to l10n in this properties file.

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bug https://bugs.openjdk.java.net/browse/JDK-8159713
Make the non-translated keywords clear to translator in jar.properties

Translator would translate the keywords if we don't tell the translation team. As Alan suggested, enclosing the keywords 
with quote would help translation team understand the words shouldn't be translated.

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bug https://bugs.openjdk.java.net/browse/JDK-8161183

the char sequence '\n\' is necessary for correct line break.

Thanks,
Leo