auto-completing nix examples

[KiaraGrouwstra]

using Nix LSP nixd's nix-community/nixd#415, in vscode i can auto-complete example values.

in helix however, such suggestions show up as part of an auto-complete suggestion:

... but then when pressing Enter to accept the suggestion, instead such example suggestions appear not included in the accepted auto-completion:

i'm not super familiar with LSP, but i felt like auto-completing such example suggestions might add value as well.

is this perhaps something about that vscode extension not following LSP best practice, or might this be an addition viable for helix as well?

version: helix 24.3 (2cadec0b)

[gabydd]

this is part of #395 and will be fixed by #9801