t8*: adjust the references to the default branch name "main"

[git] / t / chainlint / nested-subshell.test

(
        cd foo &&
        (
                echo a &&
                echo b
        ) >file &&

        cd foo &&
        (
# LINT: nested multi-line subshell not presently checked for missing "&&"
                echo a
                echo b
        ) >file
)