What is the impact of the "Fill-In-the-Middle" (FIM) technique on GitHub Copilot's code suggestions?

Restricts Copilot to use only external databases for generating code suggestions.

Allows Copilot to generate suggestions based only on the prefix of the code.

Ignores both the prefix and suffix of the code, focusing only on user comments for context.

Improves suggestions by considering both the prefix and suffix of the code, filling in the middle part more accurately.