feat: tokenizers (#429)

* feat: tokenizers

This reverts commit d5a4db8321.

* fix(inputs): #422

Signed-off-by: Aaron Pham <contact@aarnphm.xyz>

---------

Signed-off-by: Aaron Pham <contact@aarnphm.xyz>

lua/avante/providers/gemini.lua

@@ -6,6 +6,7 @@ local Clipboard = require("avante.clipboard")
 local M = {}
 
 M.api_key_name = "GEMINI_API_KEY"
+M.tokenizer_id = "google/gemma-2b"
 
 M.parse_message = function(opts)
   local message_content = {}