[Issue 19442] multiple argument string mixin dont support char literals

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19442

--- Comment #3 from Basile-z <b2.temp at gmx.com> ---
Second bug is now there https://issues.dlang.org/show_bug.cgi?id=19775

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