feature: limit columns count to 1 in the helix mode

[fpohtmeh]

Did you check the docs?

• [X] I have read all the which-key.nvim docs

Is your feature request related to a problem? Please describe.

The newly released which-key has a helix preset! But for some mappings, it displays two columns instead of one. The original Helix editor never displays 2 columns.

Describe the solution you'd like

Which key window always has a single-column

Describe alternatives you've considered

Add some option to limit column count

Additional context

Nvim 0.10.0 LazyVim 12.28.0 Which-key 05bd870

[folke]

You could've changed this yourself with opts.layout.width, but it makes sense to add this to the helix preset by default