Merging r368549:
    ------------------------------------------------------------------------
    r368549 | hokein | 2019-08-12 11:35:04 +0200 (Mon, 12 Aug 2019) | 11 lines
    
    [clangd] Drop diags from non-written #include.
    
    Summary: This would fix that we show weird diagnostics on random lines of the main file.
    
    Reviewers: ilya-biryukov
    
    Subscribers: MaskRay, jkorous, arphaman, kadircet, cfe-commits
    
    Tags: #clang
    
    Differential Revision: https://reviews.llvm.org/D66074
    ------------------------------------------------------------------------
    
    llvm-svn: 368683