feat(nix): nix and back again

I tried Nix, but it had too many downsides so I removed it.

1. Didn't like that all files are immutable and simple config changes
need a complete rebuild.
2. Setting up a new Mac didn't work as smoothly as promised. Not worth
the effort.
3. It sucked a lot to always have to type in the password twice on each
darwin-rebuild
4. It solves problems I never had.

.config/nvim/lua/plugins/dial.lua

@@ -0,0 +1,32 @@
+-- Enhanced increment/decrement
+-- https://github.com/monaqa/dial.nvim
+return {
+  "monaqa/dial.nvim",
+  config = function()
+    local augend = require("dial.augend")
+    local opts = { noremap = true, silent = true }
+
+    require("dial.config").augends:register_group({
+      default = {
+        augend.constant.alias.bool,
+        augend.constant.alias.de_weekday,
+        augend.constant.alias.de_weekday_full,
+        augend.constant.new({ elements = { "before", "after" } }),
+        augend.constant.new({ elements = { "left", "right" } }),
+        augend.constant.new({ elements = { "let", "const" } }),
+        augend.constant.new({ elements = { "start", "end" } }),
+        augend.date.alias["%d.%m.%Y"],
+        augend.hexcolor.new({ case = "lower" }),
+        augend.integer.alias.decimal_int,
+        augend.semver.alias.semver,
+      },
+    })
+
+    vim.keymap.set("n", "<C-a>", require("dial.map").inc_normal(), opts)
+    vim.keymap.set("n", "<C-x>", require("dial.map").dec_normal(), opts)
+    vim.keymap.set("v", "<C-a>", require("dial.map").inc_visual(), opts)
+    vim.keymap.set("v", "<C-x>", require("dial.map").dec_visual(), opts)
+    vim.keymap.set("v", "g<C-a>", require("dial.map").inc_gvisual(), opts)
+    vim.keymap.set("v", "g<C-x>", require("dial.map").dec_gvisual(), opts)
+  end,
+}