[Issue 19552] -transition is non-intuitive to use - the flag should list options by default

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19552

--- Comment #1 from Seb <greeenify at gmail.com> ---
PR https://github.com/dlang/dmd/pull/9205

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