dmd.deprecation-limit.dd

Deprecation warnings are now also limited by `-verrors`

By default, the compiler stops after 20 error messages, unless a different amount is specified by passing e.g. `-verrors=50` or `-verrors=0` for no limit.
This error limit now also applies to deprecation messages, so the command line isn't flooded with hundreds of them when compiling a big project that hasn't fixed all deprecations yet.

---
deprecated void f()
{
}

void main()
{
    f();
    f();
    f();
    f();
}
---

$(CONSOLE
> dmd -verrors=3 app.d
app.d(7): Deprecation: function `app.f` is deprecated
app.d(8): Deprecation: function `app.f` is deprecated
app.d(9): Deprecation: function `app.f` is deprecated
1 deprecation warning omitted, use `-verrors=0` to show all
)