[llvm] [llvm-cov] let text mode divider honor `--show-branch-summary` `--show-region-summary` etc (PR #96016)

[Hana Dusíková via llvm-commits]

hanickadot wrote:

I also wonder why `missed functions` is not colored. But it's not about your PR.

https://github.com/llvm/llvm-project/pull/96016