client/container: disable shellcheck warning for DOCKER_FINANCE_DEBUG

If it's not set or set to false, then it's expected to be not true.

client/src/docker/completion.bash

@@ -23,6 +23,8 @@
 #   `export DOCKER_FINANCE_DEBUG=true && . ~/.bashrc`
 #
 # and then proceed to call `docker-finance` / `dfi` with your commands.
+
+# shellcheck disable=SC2154
 [ "$DOCKER_FINANCE_DEBUG" == true ] && set -xv
 
 # If not yet installed, gracefully exit