[Issue 13522] Let's use '_' underscore as official ignore value

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13522

--- Comment #5 from bearophile_hugs at eml.cc ---
There are plans to totally disallow the use of "_" as variable name in Java:

http://openjdk.java.net/jeps/213

>In addition, using underscore ("_") as an identifier, which generates a warning as of Java SE 8, should be turned into an error in Java SE 9.<

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