feat(doctor): detect active preexec framework (#1955)

* feat(doctor): check active preexec framework

To check if "blesh" or "bash-preexec" is loaded and active in the
current Bash session where `atuin doctor` is called, we make the Atuin
integration script for Bash to set the environment variable
`ATUIN_PREEXEC_BACKEND` and store a string when it detects "blesh" or
"bash-preexec".

To check whether the obtained ATUIN_PREEXEC_BACKEND is set by the
current session, we record SHLVL in ATUIN_PREEXEC_BACKEND and check if
it matches SHLVL of the current process.

* feat(doctor): detect the case where Atuin is initialized before blesh

0 files changed, 0 insertions, 0 deletions