Improve the color picker plugin
- The regex color matching is simplified
- Defaults are tweaked (do not match named colors and translucent colors)
- Fixed color note updating (e.g. for search and replace)
This MR does not address, e.g. the proper handling of transparent colors and the per-file type configuration
Sorry about the barrage of commits. I kept the "outdated" commits (e.g. jbatrina/kate@f85b75fd) to preserve development history, but I'll remove them if needed.