Quoted backtick command substitution replacement doesn't unescape quotes

[Ashymad]

Before formatting:

$ echo "`echo \"foobar\"`"
foobar

After formatting:

$ echo "$(echo \"foobar\")"
"foobar"

Solution: quotes in a quoted backtick substitution should be unescaped

$ echo "$(echo "foobar")"
foobar

[mvdan]

Seems similar to https://github.com/mvdan/sh/issues/1041, thanks for reporting.