Trim off <|file_separator|> from autocomplete completion for Google Models

[hayden-cardwell]

Validations

• [x] I believe this is a way to improve. I'll try to join the Continue Discord for questions
• [x] I'm not able to find an open issue that requests the same enhancement

Problem

When using Google models for FIM/AutoComplete, they will sometimes return <|file_separator|> at the end of their completion. This results in the end-users inability to use the autocomplete completion without removing <|file_separator|> manually for each suggestion.

Solution

Add the following bit of code to the postprocessCompletion function within core/autocomplete/postprocessing/index.ts

if (
    (llm.model.includes("gemini") || llm.model.includes("gemma")) &&
    completion.endsWith("<|file_separator|>")
  ) {
    // "<|file_separator|>" is 18 characters long
    completion = completion.slice(0, -18);
  }

I would like to submit the PR to have this merged, but I'm attempting to follow the contribution guide by creating an issue first. Please let me know how to proceed.