fix(amazonq): Let Enter invoke auto completion more consistently

[leigaol]

Problem

The VS Code provideInlineCompletionCallback may not trigger when Enter is pressed, especially in Python files

Solution

manually make this trigger. In case of duplicate, the provideInlineCompletionCallback is already debounced

---

• Treat all work as PUBLIC. Private feature/x branches will not be squash-merged at release time.
• Your code changes must meet the guidelines in CONTRIBUTING.md.
• License: I confirm that my contribution is made under the terms of the Apache 2.0 license.

[github-actions]

• This pull request modifies code in src/* but no tests were added/updated.
  • Confirm whether tests should be added or ensure the PR description explains why tests are not required.