feat(treesitter-context): which-key toggle (#4059)

## Description

Add a which-key toggle for treesitter-context

## Screenshots


![image](https://github.com/user-attachments/assets/28c02607-a7e8-409c-a190-4fd2db85e8bb)

## Checklist

- [x] I've read the
[CONTRIBUTING](https://github.com/LazyVim/LazyVim/blob/main/CONTRIBUTING.md)
guidelines.

lua/lazyvim/plugins/extras/ui/treesitter-context.lua

@@ -1,21 +1,22 @@
 -- Show context of the current function
 return {
   "nvim-treesitter/nvim-treesitter-context",
-  event = "LazyFile",
-  opts = { mode = "cursor", max_lines = 3 },
-  keys = {
-    {
-      "<leader>ut",
-      function()
-        local tsc = require("treesitter-context")
-        tsc.toggle()
-        if LazyVim.inject.get_upvalue(tsc.toggle, "enabled") then
-          LazyVim.info("Enabled Treesitter Context", { title = "Option" })
+  event = "VeryLazy",
+  opts = function()
+    local tsc = require("treesitter-context")
+
+    LazyVim.toggle.map("<leader>ut", {
+      name = "Treesitter Context",
+      get = tsc.enabled,
+      set = function(state)
+        if state then
+          tsc.enable()
         else
-          LazyVim.warn("Disabled Treesitter Context", { title = "Option" })
+          tsc.disable()
         end
       end,
-      desc = "Toggle Treesitter Context",
-    },
-  },
+    })
+
+    return { mode = "cursor", max_lines = 3 }
+  end,
 }