Duplicate include suggestions are provided that resolve to the same file

[sean-mcmanus]

Use an includePath of ${workspaceFolder} and ${workspaceFolder}/sub.

Use test1.cpp code

#include "sub/sub1.h"

int main()
{
    return sub1();
}

With sub1.h

#if 0
int sub1();
#endif

Bug: It incorrectly suggests to add "sub1.h" when that already is included via #include "sub/sub1.h due to the includePath item ${workspaceFolder}/sub. This bug doesn't repro with VS.