info: print the script description and path in devenv info

[sandydoo]

Adds the script's description and its path to the output of devenv info.
Preview for devenv:

# processes
- docs: exec /nix/store/1vi1k0wy7a86g8i5imypw1p2g1g2bjl9-docs
- tailwind: exec /nix/store/ln9gvm1gkmii8bxr51n4r54c8j1w3991-tailwind

# scripts
- devenv-generate-doc-options: Generate option docs.
  /nix/store/f3kp77kfxl08nqlpzdmkykqnf1cwnfhc-devenv-generate-doc-options

- devenv-generate-docs: Generate lists of all languages and services.
  /nix/store/ycwim9lpm0azqkh77sysr3j2kw17m5fc-devenv-generate-docs

- devenv-generate-languages-example: Generate an example enabling every supported language.
  /nix/store/17x10g90jicnadi2ixm5as2gd9ch6vi6-devenv-generate-languages-example

- devenv-test-cli: Test devenv CLI.
  /nix/store/jiyllnk1sm3bamhrkbh38lhhh5svhqij-devenv-test-cli

Suggested by @karfau on discord.