feat: add vim.text module (#26069)

test/functional/lua/text_spec.lua

@@ -0,0 +1,23 @@
+local helpers = require('test.functional.helpers')(after_each)
+local clear = helpers.clear
+local eq = helpers.eq
+
+describe('vim.text', function()
+  before_each(clear)
+
+  describe('hexencode() and hexdecode()', function()
+    it('works', function()
+      local cases = {
+        { 'Hello world!', '48656C6C6F20776F726C6421' },
+        { '😂', 'F09F9882' },
+      }
+
+      for _, v in ipairs(cases) do
+        local input, output = unpack(v)
+        eq(output, vim.text.hexencode(input))
+        eq(input, vim.text.hexdecode(output))
+      end
+    end)
+  end)
+end)
+