Add comments and clarify errors in neverallow

Sample of new error for violation:

error: system/bt/gd/rust/topshim/macros/Android.bp:10:1: module
"libtopshim_macros" variant "linux_glibc_x86_64": violates neverallow
requirements. Not allowed:
        module types: ["rust_benchmark" "rust_benchmark_host"
"rust_binary" "rust_binary_host" "rust_library" "rust_library_dylib"
"rust_library_rlib" "rust_ffi" "rust_ffi_shared" "rust_ffi_static"
"rust_fuzz" "rust_library_host" "rust_library_host_dylib"
"rust_library_host_rlib" "rust_ffi_host" "rust_ffi_host_shared"
"rust_ffi_host_static" "rust_proc_macro" "rust_test" "rust_test_host"]
      EXCEPT in dirs: ["device/google/cuttlefish/"
"external/adhd/" "external/crosvm/" "external/libchromeos-rs/"
"external/minijail/" "external/rust/" "external/selinux/libselinux/"
"external/uwb/" "external/vm_tools/p9/"
"frameworks/native/libs/binder/rust/" "frameworks/proto_logging/stats/"
"packages/modules/DnsResolver/" "packages/modules/Virtualization/"
"prebuilts/rust/" "system/core/libstats/pull_rust/"
"system/extras/profcollectd/" "system/extras/simpleperf/"
"system/hardware/interfaces/keystore2/" "system/librustutils/"
"system/logging/liblog/" "system/logging/rust/" "system/nfc/"
"system/security/" "system/tools/aidl/"
"tools/security/fuzzing/example_rust_fuzzer/"
"tools/security/fuzzing/orphans/" "vendor/"]

Old error:

error: system/bt/gd/rust/topshim/macros/Android.bp:10:1: module
"libtopshim_macros" variant "linux_glibc_x86_64": neverallow
-dir:device/google/cuttlefish/* -dir:external/adhd/*
-dir:external/crosvm/* -dir:external/libchromeos-rs/*
-dir:external/minijail/* -dir:external/rust/*
-dir:external/selinux/libselinux/* -dir:external/uwb/*
-dir:external/vm_tools/p9/* -dir:frameworks/native/libs/binder/rust/*
-dir:frameworks/proto_logging/stats/*
-dir:packages/modules/DnsResolver/*
-dir:packages/modules/Virtualization/* -dir:prebuilts/rust/*
-dir:system/core/libstats/pull_rust/* -dir:system/extras/profcollectd/*
-dir:system/extras/simpleperf/*
-dir:system/hardware/interfaces/keystore2/* -dir:system/librustutils/*
-dir:system/logging/liblog/* -dir:system/logging/rust/*
-dir:system/nfc/* -dir:system/security/* -dir:system/tools/aidl/*
-dir:tools/security/fuzzing/example_rust_fuzzer/*
-dir:tools/security/fuzzing/orphans/* -dir:vendor/*
type:"rust_benchmark" type:"rust_benchmark_host type:rust_binary
type:rust_binary_host type:rust_library type:rust_library_dylib
type:rust_library_rlib type:rust_ffi type:rust_ffi_shared
type:rust_ffi_static type:rust_fuzz type:rust_library_host
type:rust_library_host_dylib type:rust_library_host_rlib
type:rust_ffi_host type:rust_ffi_host_shared type:rust_ffi_host_static
type:rust_proc_macro type:rust_test type:rust_test_host

Test: go test soong tests
Change-Id: I1a7ee6bbc8258dfffa5a76f02c12fb1e54fdba1a