nvim/which-key: register additional window binds

which-key only knows about registered keymaps and user-created keymaps.
Builtin binds without a remap aren't known to which-key unless
registered.

See folke/which-key.nvim#583

nvim/config/keymaps.nix

@@ -8,14 +8,37 @@
           proxy = "<C-w>";
           group = "windows";
         }
+        {
+          __unkeyed-1 = "<c-w>c";
+          desc = "Close current window";
+        }
+        {
+          __unkeyed-1 = "<c-w>H";
+          desc = "Move current window to the far left";
+        }
+        {
+          __unkeyed-1 = "<c-w>J";
+          desc = "Move current window to the very bottom";
+        }
+        {
+          __unkeyed-1 = "<c-w>K";
+          desc = "Move current window to the very top";
+        }
+        {
+          __unkeyed-1 = "<c-w>L";
+          desc = "Move current window to the far right";
+        }
+
         {
           __unkeyed-1 = "<leader>b";
           group = "buffers";
         }
+
         {
           __unkeyed-1 = "<leader>r";
           group = "refactoring";
         }
+
         {
           __unkeyed-1 = "<leader>f";
           group = "files";