Use a longer debounce delay for short search strings

This gives the user more time to type in their whole query before a search blocks the main thread.

Searches for short strings often have many results that aren't really useful to the user. They also take much longer to process.

This commit increases the debounce delay to 200ms for short strings three characters long or less. Longer strings still have the 50ms delay. Hopefully, this is a good balance between avoiding slowdowns for short strings and providing a snappy interactive experience for long strings.