Initially #82897 prevented
non-visible options from being rendered in the manual, but
visible-but-internal options were still being recursed into. This fixes
this, aligning the recurse condition here with the one in
make-options-doc/default.nix

lib/options: Don't show internal suboption in the manual

Initially NixOS#82897 prevented
non-visible options from being rendered in the manual, but
visible-but-internal options were still being recursed into. This fixes
this, aligning the recurse condition here with the one in
make-options-doc/default.nix

lib/modules: Implement module-builtin assertions

This implements assertions/warnings supported by the module system directly,
instead of just being a NixOS option (see
nixos/modules/misc/assertions.nix).

This has the following benefits:
- It allows cleanly redoing the user interface. The new
  implementation specifically allows disabling assertions or
  converting them to warnings instead.
- Assertions/warnings can now be thrown easily from within
  submodules, which previously wasn't possible and needed workarounds.

nixos/assertions: Use module-builtin assertion implementation

lib/modules: Use module-builtin assertions for mkRemovedOptionModule and co.

nixos/modules: Allow options to be coerced to a string for convenience

nixos/modules: Expose the internal module in the top-level documentation

nixos/docs: Update assertion docs for new module-builtin ones

lib/tests: Implement generalized checkConfigCodeOutErr for module tests

lib/tests: Add tests for module-builtin assertions

lib/modules: Rename _module.assertions to _module.checks

lib/modules: Remove _module.checks.*.triggerPath as it's not necessary

Previously this option was thought to be necessary to avoid infinite
recursion, but it actually isn't, since the check evaluation isn't fed
back into the module fixed-point.

lib/modules: _module.check should always be internal

Honestly this option should probably just be removed

lib/modules: Introduce _module.checks.*.check

Previously the .enable option was used to encode the condition as well,
which lead to some oddness:
- In order to encode an assertion, one had to invert it
- To disable a check, one had to mkForce it

By introducing a separate .check option this is solved because:
- It can be used to encode assertions
- Disabling is done separately with .enable option, whose default can be
  overridden without a mkForce

lib/modules: Prefix mkRemovedOptionModule & co. check names

To avoid name clashes

Co-authored-by: Robert Hensing <robert@roberthensing.nl>

bla

Initially NixOS/nixpkgs#82897 prevented
non-visible options from being rendered in the manual, but
visible-but-internal options were still being recursed into. This fixes
this, aligning the recurse condition here with the one in
make-options-doc/default.nix