On macOS I've set my login shell to bash instead of zsh, which became the default in Catalina (Terminal > Preferences > General > Shells open with: > /bin/bash).
But when I shell escape from vi (from Terminal), the shell command is still run by zsh.
How can I make vi spawn not zsh but rather bash (or at least whatever's in Terminal > Preferences), so a shell escape can run commands defined in ~/.bashrc?