Summary:
this component is a wrapper around the autocomplete input component (previous diff) and the completions list component (already used in the current autocomplete).
it handles keyboard actions, such as backspace, entering characters, or moving the cursor left/right. it also handles which autocomplete suggestions to show depending on the users cursor position.

Test Plan: jest test

Reviewers: nserrino, zasgar, #engineering

Reviewed By: nserrino, #engineering

Differential Revision: https://phab.corp.pixielabs.ai/D5405

GitOrigin-RevId: 7ae31c7e64cff08ea51790babe063d23a538d503