`tomlFormat.generate` doesn't chomp tab indentation

[Kreyren]

Transferred from NixOS/nixpkgs#251823 as instructed on matrix due to GitHub's issue transfering not working correctly

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Describe the bug

Issues observed in home-manager's program.starship.settings.format as described in nix-community/home-manager#4382

Steps To Reproduce

Declare tomlFormat.generate with 2nd argument that is using tabs for indentation parsed through '' string as shown in linked issue.

Expected behavior

Work without issues on tab indentation

Screenshots

Additional context

Affected line:

https://github.com/NixOS/nixpkgs/blob/master/pkgs/pkgs-lib/formats.nix#L198

Discussed on matrix: https://matrix.to/#/!KqkRjyTEzAGRiZFBYT:nixos.org/$n1AQxqYcMCHglb15MfUxujcN9tISVsPvzGStK2L0Ciw?via=nixos.org&via=matrix.org&via=tchncs.de

Notify maintainers

Unsure who to notify, triage

Metadata

$ nix-shell -p nix-info --run "nix-info -m"
 - system: `"x86_64-linux"`
 - host os: `Linux 6.4.8-xanmod1, NixOS, 23.05 (Stoat), 23.05.2775.720e61ed8de1`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.13.5`
 - channels(root): `"nixos-23.05, nixos-unstable"`
 - channels(raptor): `"home-manager-23.05.tar.gz, nixpkgs-23.05, nixpkgs-unstable"`
 - nixpkgs: `/home/raptor/.nix-defexpr/channels/nixpkgs`

[infinisil]

Duplicate of #3759 or #2911

[roberth]

Unfortunately we're stuck with this behavior, it is actionable as discussed by the team, to introduce warnings for this, or move RFC 137 forward.

Closing as duplicate.