Search the trigram index too, combining the results
with the results of the "normal" fts index.
Prioritize the latter since it makes more sense to
rank whole words higher.
Processing dirs with large docs takes time and waiting till the threshold
is reached can be a bit annoying in those cases, so report if last report
was 10+ seconds ago.
group_concat() does not preserve order of the ORDRE BY rank,
making the ordering quite meaningless for pages inside a file.
The recently introduced combobox to filter on a per file basis
should anyway be prefered than any kind of grouping in queries.
So we just remove the groupings here.
"All files" in the previews tab thus should show the best results
first now, from any files part of the result set.
A GUI option to sort by page instead of rank can be considered.
In [1] it's stated that "If the values "inserted" into the text
columns as part of a 'delete' command are not the same as those
currently stored within the table, the results may be unpredictable."
It's to be assumed only inserting ftsid is unpredictable. We
have no way for a proper delete because files are not immutable
or may have been deleted.
For now the index will contain entries for files that don't exist.
They won't appear in search results as they won't be joined
in the query.
[1] https://www.sqlite.org/fts5.html#the_delete_command
Most users are not to be expected to be familiar with
sqlite's FTS syntax. It also leads to unnnecessary
arrows in some instances.
So wrap every space separated word in quotes, unless
it's already in quotes. Then we just escape those with
double-quotes.
We never used the content copy we stored. It only wasted space.
Update scheme so we do not store the content anymore. Switch
to contentless FTS approach
