Implement @deprecated

[kristoff-it]

Implements #22822

The part I'm most unsure about this implementation relates to how the build system represents -fallow-deprecated and -fno-allow-deprecated internally and how then this is reflected in the CLI invocation of build-exe and related subcommands.

[andrewrk]

Can't wait to use this immediately, like this:

    if (std.meta.hasMethod(T, "format")) {
        if (fmt.len > 0 and fmt[0] == 'f') {
            return value.format(fmt[1..], options, bw);
        } else {
            @deprecated();
            // After 0.14.0 is tagged, uncomment this next line:
            //@compileError("ambiguous format string; specify {f} to call format method, or {any} to skip it");
            //and then delete the `hasMethod` condition
            return value.format(fmt, options, bw);
        }
    }

[kristoff-it]

@andrewrk rewiew it and it's all yours :^)

[alexrp]

Failure looks related:

test
+- test-cases
   +- zig build-obj deprecated Debug native failure
error: 
========= expected: =====================
":1:13: error: found deprecated code",

========= but found: ====================
/Users/runner/work/zig/zig/zig-local-cache/o/0ffd4dc9bed490371ea1bface94a9b5e/tmp.zig:1:13: error: found deprecated code