Added more information under "Caveats" in "src Directory"

[Amila-Rukshan]

Docs: No info on environment variables in the /src folder #33110
link to the docs => https://nextjs.org/docs/advanced-features/src-directory

Bug

• Related issues linked using fixes #number
• Integration tests added
• Errors have helpful link attached, see contributing.md

Feature

• Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
• Related issues linked using fixes #number
• Integration tests added
• Documentation added
• Telemetry added. In case of a feature if it's used or not.
• Errors have helpful link attached, see contributing.md

Documentation / Examples

• Make sure the linting passes by running yarn lint

[Amila-Rukshan]

@ijjk, can I have a code review, please?

[atenie]

Hi,

I don't understand why another PR was opened... I made a PR before you that was fixing both files, not just one:

#33136

Kind regards