fix: revert max_completion_tokens to max_tokens (#1741)

README.md

@@ -67,7 +67,7 @@ For building binary if you wish to build from source, then `cargo` is required.
       model = "gpt-4o", -- your desired model (or use gpt-4o, etc.)
       timeout = 30000, -- Timeout in milliseconds, increase this for reasoning models
       temperature = 0,
-      max_completion_tokens = 8192, -- Increase this to include reasoning tokens (for reasoning models)
+      max_tokens = 8192, -- Increase this to include reasoning tokens (for reasoning models)
       --reasoning_effort = "medium", -- low|medium|high, only used for reasoning models
     },
   },