client: For filtering, prioritize exact, startsWith

[digitalcircuit]

In short

• When filtering buffers by string, prioritize relevant results first
  • Priorize by exact matches, then matches that start with the string, then all else
  • Within these priorities, everything's sorted as before
  • Makes it easier to search by exact/starting string

Criteria	Rank	Reason
Impact	★☆☆ 1/3	User-facing change in buffer filter order
Risk	★☆☆ 1/3	Order of buffer filtering (new to 0.13) will change; could be unexpected
Intrusiveness	★☆☆ 1/3	Small set of changes, shouldn't interfere with other pull requests

Rationale

It seems more likely to search for a channel/nickname with the starting letters rather than filtering by the middle, as that's how the channel/nickname list is sorted (when alphabetical sorting is enabled). Similarly, an exact match should emphasize that over any substring matches.

Quassel should prioritize results that exactly match, then start with, over the rest of the results that merely contain the filter string.

This is personal opinion, feel free to disagree!

Examples

Setup

1. Add six PMs, acar, bcar, car, careful, caring, racecar
   • E.g. /query [name]
2. Temporarily hide car
3. Search for car with buffer filter, e.g. Ctrl+S

Before

• Normal
  • acar
  • bcar
  • careful
  • caring
  • racecar
• Temporarily hidden
  • car

After

• Exact match
  • car (still temporarily hidden)
• Starts with match
  • careful
  • caring
• Normal
  • acar
  • bcar
  • racecar