Clang-Tidy: only show issues for libCellML's headers.
Clang-Tidy: only show issues for libCellML's headers.

MichaelClerx/libcellml,MichaelClerx/libcellml,nickerso/libcellml,hsorby/libcellml,nickerso/libcellml,cellml/libcellml,hsorby/libcellml,nickerso/libcellml,cellml/libcellml,cellml/libcellml,hsorby/libcellml,hsorby/libcellml,nickerso/libcellml,cellml/libcellml,MichaelClerx/libcellml