[Issue 15853] std.random save methods must be const

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=15853

--- Comment #7 from Stepan Rogonov <rogonovstepan at gmail.com> ---
(In reply to hsteoh from comment #6)
> Let's not close it until the PR is merged.

Sorry..

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