Fix the parsing of Baloo query `searchString` to represent its parameters properly in the search box:
# Baloo terms (`rating`, `modified`) are added to the user search text: {F7575590}
# Extra quotes are added to the search text: https://bugs.kde.org/show_bug.cgi?id=
# Doesn't properly selects `Filename` or `Content` (just uses previous selection)
This revision supersedes D24422, by making the fixes on the new dolphin query model, instead of directly on the UI.
BUG: 412952
FIXED IN: 19.12 / 20.04?
Depends on: D25258