feat(lua): add ringbuffer (#22894)

https://en.wikipedia.org/wiki/Circular_buffer

test/functional/lua/vim_spec.lua

@@ -3040,6 +3040,46 @@ describe('lua stdlib', function()
 
     eq(4, exec_lua [[ return vim.re.match("abcde", '[a-c]+') ]])
   end)
+
+  it("vim.ringbuf", function()
+    local results = exec_lua([[
+      local ringbuf = vim.ringbuf(3)
+      ringbuf:push("a") -- idx: 0
+      local peeka1 = ringbuf:peek()
+      local peeka2 = ringbuf:peek()
+      local popa = ringbuf:pop()
+      local popnil = ringbuf:pop()
+      ringbuf:push("a") -- idx: 1
+      ringbuf:push("b") -- idx: 2
+
+      -- doesn't read last added item, but uses separate read index
+      local pop_after_add_b = ringbuf:pop()
+
+      ringbuf:push("c") -- idx: 3 wraps around, overrides idx: 0 "a"
+      ringbuf:push("d") -- idx: 4 wraps around, overrides idx: 1 "a"
+      return {
+        peeka1 = peeka1,
+        peeka2 = peeka2,
+        pop1 = popa,
+        pop2 = popnil,
+        pop3 = ringbuf:pop(),
+        pop4 = ringbuf:pop(),
+        pop5 = ringbuf:pop(),
+        pop_after_add_b = pop_after_add_b,
+      }
+    ]])
+    local expected = {
+      peeka1 = "a",
+      peeka2 = "a",
+      pop1 = "a",
+      pop2 = nil,
+      pop3 = "b",
+      pop4 = "c",
+      pop5 = "d",
+      pop_after_add_b = "a",
+    }
+    eq(expected, results)
+  end)
 end)
 
 describe('lua: builtin modules', function()