Feature request: Option to underline without end_col

[jclem]

Some linters do not provide an end_col, so they don't get underlined even if vim.diagnostics is configured to do so.

In VSCode, the editor essentially sets a fake end column to the end of the line on which the error occurs, so that there's still an underline visible. It would be useful if nvim-lint offered a similar option via configuration. This makes it much easier to identify where the issue begins.

[mfussenegger]

I think this might be something to add in nvim core - an option that causes nvim to underline to the eol if end_col is absent in the vim.Diagnostic structure.

Then it could likely get configured via vim.diagnostic.config { underline = {...} }

Could you open a feature request in the neovim repo?