[Issue 21216] SortedRange.empty should be const, .front should be inout

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21216

--- Comment #2 from dlangBugzillaToGithub <robert.schadek at posteo.de> ---
THIS ISSUE HAS BEEN MOVED TO GITHUB

https://github.com/dlang/phobos/issues/10437

DO NOT COMMENT HERE ANYMORE, NOBODY WILL SEE IT, THIS ISSUE HAS BEEN MOVED TO
GITHUB

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