dmd foreach loops throw exceptions on invalid UTF sequences, use replacementDchar instead

[zjh]

On Thursday, 4 November 2021 at 08:24:59 UTC, zjh wrote:

The `fundamental` problem is that we should provide users with 
`options` at compile time, not we `choose` for users.
If you `choose` for users, there will always be dissatisfaction.
You provide options ,and Users choose according to their needs.

`auto decoding` and `utf8 string encoding` are both like this. If 
you choose for users, some people are always not happy.