attribute in macro can break syntax highlighting

[hokein]

moved from https://github.com/clangd/clangd/issues/385

The code with a problem is:

#pragma once

#if 1
#   define MACRO(attr) [[attr]]
#else
#   define MACRO(attr)
#endif

struct S {
    MACRO(deprecated("some unrecognized string size() some unrecognized string"))
    int f() { return 0; }
};

It looks like:

vscode 1.45.0 without any cpp extension.

[ytimenkov]

And another example here: https://github.com/microsoft/vscode-cpptools/issues/6560