Fix panic message for removed features

[CatMe0w]

When a deprecated feature is used after its scheduled removal, sing-box used to panic with an internal name (e.g. invalid deprecated note: bad-match-source), which confused end users.

This change makes the panic message match the deprecation notice style, so users immediately know what to change.

Full log, using sing-box version 1.12.13:

panic: invalid deprecated note: bad-match-source

goroutine 1 [running]:
github.com/sagernet/sing-box/experimental/deprecated.Note.Impending({{0x1c553b8, 0x10}, {0x1c75793, 0x1d}, {0x1c44371, 0x6}, {0x1c44377, 0x6}, {0x1c553c8, 0x10}, ...})
        github.com/sagernet/sing-box/experimental/deprecated/constants.go:33 +0x245
github.com/sagernet/sing-box/experimental/deprecated.(*stderrManager).ReportDeprecated(0xc0002c0798, {{0x1c553b8, 0x10}, {0x1c75793, 0x1d}, {0x1c44371, 0x6}, {0x1c44377, 0x6}, {0x1c553c8, ...}, ...})
        github.com/sagernet/sing-box/experimental/deprecated/stderr.go:27 +0x9c
github.com/sagernet/sing-box/experimental/deprecated.Report({0x1fb0138?, 0xc000394370?}, {{0x1c553b8, 0x10}, {0x1c75793, 0x1d}, {0x1c44371, 0x6}, {0x1c44377, 0x6}, ...})
        github.com/sagernet/sing-box/experimental/deprecated/manager.go:18 +0x59
github.com/sagernet/sing-box/route/rule.NewDefaultRule({_, _}, {_, _}, {{{0xc0003a00b0, 0x1, 0x1}, 0x0, {0x0, 0x0, ...}, ...}, ...})
        github.com/sagernet/sing-box/route/rule/rule_default.go:257 +0x4565
github.com/sagernet/sing-box/route/rule.NewRule({_, _}, {_, _}, {{0x1c45c45, 0x7}, {{{0xc0003a00b0, 0x1, 0x1}, 0x0, ...}, ...}, ...}, ...)
        github.com/sagernet/sing-box/route/rule/rule_default.go:28 +0x359
github.com/sagernet/sing-box/route.(*Router).Initialize(0xc0003a2240, {0xc00039a008?, 0x4, 0x1fc3fb8?}, {0xc00030a900, 0x2, 0x2?})
        github.com/sagernet/sing-box/route/router.go:66 +0xfe
github.com/sagernet/sing-box.New({{{0xc000331000, 0x86d, 0xe00}, {0x0, 0x0}, 0xc00033f4a0, 0xc0002c8780, 0x0, 0x0, {0x0, ...}, ...}, ...})
        github.com/sagernet/sing-box/box.go:196 +0x1605
main.create()
        github.com/sagernet/sing-box/cmd/sing-box/cmd_run.go:137 +0x1f8
main.run()
        github.com/sagernet/sing-box/cmd/sing-box/cmd_run.go:174 +0x105
main.init.func26(0xc00030a100?, {0x1c4241f?, 0x4?, 0x1c42423?})
        github.com/sagernet/sing-box/cmd/sing-box/cmd_run.go:30 +0x17
github.com/spf13/cobra.(*Command).execute(0x2e849e0, {0xc0002d37c0, 0x4, 0x4})
        github.com/spf13/cobra@v1.9.1/command.go:1019 +0xae7
github.com/spf13/cobra.(*Command).ExecuteC(0x2e7fce0)
        github.com/spf13/cobra@v1.9.1/command.go:1148 +0x465
github.com/spf13/cobra.(*Command).Execute(...)
        github.com/spf13/cobra@v1.9.1/command.go:1071
main.main()
        github.com/sagernet/sing-box/cmd/sing-box/main.go:8 +0x1e