Auto-Complete for Search Box

Good suggestion. The question is what we auto-complete to? I suppose package names, possibly tags...

(we could also have jump-to-package on exact match. but we'd want to not force that on users, but only make it optional -- need good ui for that)

Start by clarifying what the Search Box should autocomplete: package names, tags, or both. Define whether exact package matches should offer an optional jump-to-package action, and consider the UI needed to avoid forcing that behavior; done means the target suggestions and optional exact-match interaction are agreed.

Written by the indexing model from the issue text.