fix issues 13315, 13316, 13317 - std.getopt woes

Issue 13315 - std.getopt: implicit help option doesn't work without config.passThrough
https://issues.dlang.org/show_bug.cgi?id=13315

Issue 13316 - std.getopt: implicit help option breaks the next argument
https://issues.dlang.org/show_bug.cgi?id=13316

Issue 13317 - std.getopt: endOfOptions broken when it doesn't look like an option
https://issues.dlang.org/show_bug.cgi?id=13317