Bug: compilation failed when I don't have frunk-core as dependency

[juchiast]

error[E0433]: failed to resolve: could not find `frunk_core` in the list of imported crates
  --> crates/flow/src/flow_set.rs:21:10
   |
21 | #[derive(frunk::LabelledGeneric)]
   |          ^^^^^^^^^^^^^^^^^^^^^^ could not find `frunk_core` in the list of imported crates
   |
   = note: this error originates in the derive macro `frunk::LabelledGeneric` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider importing this module
   |
1  + use frunk::labelled;
   |

error[E0433]: failed to resolve: could not find `frunk_core` in the list of imported crates
  --> crates/flow/src/flow_set.rs:21:10
   |
21 | #[derive(frunk::LabelledGeneric)]
   |          ^^^^^^^^^^^^^^^^^^^^^^ could not find `frunk_core` in the list of imported crates
   |
   = note: this error originates in the derive macro `frunk::LabelledGeneric` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider importing this module
   |
1  + use frunk::hlist;
   |

error[E0433]: failed to resolve: could not find `frunk_core` in the list of imported crates
  --> crates/flow/src/flow_set.rs:21:10
   |
21 | #[derive(frunk::LabelledGeneric)]
   |          ^^^^^^^^^^^^^^^^^^^^^^ could not find `frunk_core` in the list of imported crates
   |
   = note: this error originates in the derive macro `frunk::LabelledGeneric` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider importing this module
   |
1  + use frunk::labelled::chars;

frunk should be able to work on its own.

[lloydmeta]

Oof yeah, this is one of those annoying/tough nuts to crack

Likely comes from this kind of thing in the macro:

https://github.com/lloydmeta/frunk/blob/ffba8cfa144b8ed02942271a3ea45006100cd029/derives/src/derive_labelled_generic.rs#L36

I'm not sure how best we can solve this so that it works when using just frunk while allowing it to work with piecemeal dependencies.