[clang] [clang-tools-extra] [lldb] [llvm] [mlir] [openmp] [polly] [docs] Remove "referenced by" output (PR #182876)

[Timm Baeder via llvm-commits]

tbaederr wrote:

I think all the `doxygen.cfg.in` files not covered by this PR are already disabling the relevant output, e.g.:
https://github.com/llvm/llvm-project/blob/bb1d53bbd8726160ed2e45bb4170454b4d8d2d9b/flang/docs/doxygen.cfg.in#L915-L925

https://github.com/llvm/llvm-project/pull/182876