how to source as union of lsp and buffer?

[michelrandahl]

When writing code I would like the source to always be a union of lsp and buffer. I have looked at the documentation again and again and tried different things, but I cannot figure out how to achieve this.

[saghen]

sources.providers.lsp.fallbacks = {}, default is { 'buffer' }, so buffer only shows when LSP returns no items

[saghen]

Added additional docs for this: a499c6a