Update to (somewhat?) dendritic pattern

Heavily inspired by https://github.com/Doc-Steve/dendritic-design-with-flake-parts.

> Atomic commits? Never heard of them!

modules/programs/nixvim/_nixvim-config/plugins/cmp/keymaps.nix

@@ -0,0 +1,16 @@
+{ ... }: {
+  keymaps = [
+    {
+      key = "grd";
+      action = "<cmd>Telescope lsp_definitions<CR>";
+      mode = "n";
+      options.desc = "LSP: [G]oto [D]efinition";
+    }
+    {
+      key = "gri";
+      action = "<cmd>Telescope lsp_implementations<CR>";
+      mode = "n";
+      options.desc = "LSP: [G]oto [I]mplementations";
+    }
+  ];
+}