llama.vim : bump generation time limit to 3s [no ci]

examples/llama.vim

@@ -81,7 +81,7 @@ let s:default_config = {
     \ 'n_suffix':         64,
     \ 'n_predict':        128,
     \ 't_max_prompt_ms':  500,
-    \ 't_max_predict_ms': 1000,
+    \ 't_max_predict_ms': 3000,
     \ 'show_info':        2,
     \ 'auto_fim':         v:true,
     \ 'max_line_suffix':  8,