Move lsp config to local file structure

.config/nvim/lsp/digestif.lua

@@ -0,0 +1,16 @@
+---@brief
+---
+--- https://github.com/astoff/digestif
+---
+--- Digestif is a code analyzer, and a language server, for LaTeX, ConTeXt et caterva. It provides
+---
+--- context-sensitive completion, documentation, code navigation, and related functionality to any
+---
+--- text editor that speaks the LSP protocol.
+
+---@type vim.lsp.Config
+return {
+  cmd = { 'digestif' },
+  filetypes = { 'tex', 'plaintex', 'context' },
+  root_markers = { '.git' },
+}