feat(nixos): migrate system configuration

configs/nixos/modules/shell/nvim/config.lua

@@ -0,0 +1,36 @@
+-- Imperative configuration that has no typed nixvim option: the colorscheme call and autocmds.
+
+-- gbprod/nord.nvim.
+require("nord").setup({
+  transparent = true,
+})
+vim.cmd.colorscheme("nord")
+
+-- Conceal markdown syntax in markdown buffers.
+-- conceallevel is window-local, so it is set with opt_local when the filetype
+-- is applied to the buffer's window.
+vim.api.nvim_create_autocmd("FileType", {
+  pattern = "markdown",
+  callback = function()
+    vim.opt_local.conceallevel = 2
+  end,
+})
+
+-- Soft-wrap prose buffers without inserting line breaks.
+vim.api.nvim_create_autocmd("FileType", {
+  pattern = { "gitcommit", "markdown", "text" },
+  callback = function()
+    vim.opt_local.wrap = true
+    vim.opt_local.linebreak = true
+    vim.opt_local.breakindent = true
+  end,
+})
+
+-- Turn line blame off again once the Neogit status buffer is closed.
+vim.api.nvim_create_autocmd("BufUnload", {
+  callback = function(args)
+    if vim.bo[args.buf].filetype == "NeogitStatus" then
+      require("gitsigns").toggle_current_line_blame(false)
+    end
+  end,
+})