Can't make it work inside shell constructs

[nkakouros]

Describe the bug

Inside some shell constructs, eg functions, I don't get rainbow parenetheses or brackets.

To Reproduce

:e test.sh
(((((())))))
{{{{}}}}
function() {
  (((())))
}

Expected behavior

I would expect the parentheses to keep being colored.

Screenshots

In the example in the README, for vim there is a containedin key. Should this be added any time such "nested" highlighting is needed? If so, how could I get this working for bash?

[luochen1990]

Could you please read the README/Troubleshooting part and try to solve it?