Fix %*s handling by formattedRead()

[nicolo-mn]

This PR addresses issue #10598. The problem lies in the lack of handling for certain specifiers in the skipData function of std/format/internal/read.d. The switch statement only handles %c, %d and %u. Handling of %s was added but the problem is analogous in the case of other specifiers. For example, the program:

import std.format;
import std.stdio;
void main()
{
    string str = "3.14159 0.0 6.28318";
    double pi, tau;
    str.formattedRead("%f %*f %f", pi, tau);
    writeln("Pi is: ", pi , ", Tau is: ", tau);
}

outputs this:

core.exception.AssertError@/home/nick/dlang/dmd/generated/linux/release/64/../../../../../phobos/std/format/internal/read.d(43): Format specifier not understood: %f
----------------
??:? _d_assert_msg [0x55af8fd75528]
??:? pure @safe void std.format.internal.read.skipData!(immutable(char)[], char).skipData(ref immutable(char)[], scope ref const(std.format.spec.FormatSpec!(char).FormatSpec)) [0x55af8fd4f58d]
??:? pure @safe void std.format.read.formattedRead!(immutable(char)[], char, double).formattedRead(ref immutable(char)[], const(char)[], ref double).skipUnstoredFields() [0x55af8fd51091]
??:? pure @safe uint std.format.read.formattedRead!(immutable(char)[], char, double).formattedRead(ref immutable(char)[], const(char)[], ref double) [0x55af8fd50ffa]
??:? pure @safe uint std.format.read.formattedRead!(immutable(char)[], char, double, double).formattedRead(ref immutable(char)[], const(char)[], ref double, ref double) [0x55af8fd49d4f]
??:? _Dmain [0x55af8fd49918]

Therefore, the remaining specifiers also need to be handled. Should I include them in this PR, or should I open a separate, more general issue and PR for this problem?

[dlang-bot]

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Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + phobos#10654"

[thewilsonator]

please add the test case from #10598 as a unittest.

[nicolo-mn]

Thank you for your review @thewilsonator. A unittest was added. I remain available for further changes.

[nicolo-mn]

@thewilsonator Is it possible that the checks have been interrupted without any errors? I see the message Error: The operation was canceled. but no log errors.

[thewilsonator]

Some of those time out

[nicolo-mn]

Thanks for running the tests one more time. Unfortunately, the same check on macOS 13 x64 keeps timing out for some reason. I double-checked my implementation and it seems fine to me. Do you have any ideas on what might be causing this?