chore(direnv): update .envrc

- Cleanup direnv-root file
- Set filetype for vi-like editors
- Format and lint according to shellcheck and shfmt

Author: xarvex

.envrc

@@ -1,9 +1,13 @@
+# vi: ft=bash
+
 if ! has nix_direnv_version || ! nix_direnv_version 3.0.5; then
-  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.0.5/direnvrc" "sha256-RuwIS+QKFj/T9M2TFXScjBsLR6V3A17YVoEW/Q6AZ1w="
+    source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.0.5/direnvrc" "sha256-RuwIS+QKFj/T9M2TFXScjBsLR6V3A17YVoEW/Q6AZ1w="
 fi
 
-DEVENV_ROOT_FILE="$(mktemp)"
-printf %s "${PWD}" > "${DEVENV_ROOT_FILE}"
-if ! use flake . --override-input devenv-root "file+file://${DEVENV_ROOT_FILE}"; then
+devenv_root_file="$(mktemp -t devenv-root-XXXXXXXX)"
+printf %s "${PWD}" >"${devenv_root_file}"
+if ! use flake . --override-input devenv-root "file+file://${devenv_root_file}"; then
     printf '%s\n' "devenv could not be built. The devenv environment was not loaded. Make the necessary changes to devenv.nix and hit enter to try again." >&2
 fi
+rm "${devenv_root_file}"
+unset devenv_root_file