feat(lsp): add optional slint lsp config

lua/plugins/20-lsp.lua

@@ -22,6 +22,9 @@ return {
                     "--enable-config", -- Enable .clangd and clangd.yaml files
                 },
             },
+            slint_lsp = {
+                root_dir = function() end, -- Fix missing root_dir issue in neoconf (lspconfig doesn't define it...)
+            },
         },
     },
 }