* fix: get file lock forcibly
When Neovim ends without removing file locks, it will fail to open
frecency ever because file locks remain. This fix makes it remove file
locks when all attempts fail forcibly.
* test: avoid error in Windows
In Windows, unclosed file cannot be removed, so close it before
unlinking.
* feat: retry to unlink when it fails
* refactor: make logic for Database be abstract
* feat: add logic for DB by string.dump
* fix: run with async.void to run synchronously
* test: add tests for native feature
* feat!: sort candidates by path when score is same
This is needed because candidates from SQLite is sorted by id, but ones from native is sorted by path.
* chore: clean up types
* feat: add lock/unlock feature to access DB
* test: use async version of busted
And disable benchmark tests (fix later)
* test: add tests for file_lock
* chore: use more explicit names
* chore: use plenary.log instead
* fix: wait async functions definitely
* feat: add migrator
* chore: fix logging
* fix: detect emptiness of the table
* fix: deal with buffer with no names
* test: loosen the condition temporarily
* test: add tests for migrator
* fix: return true when the table is not empty
* feat: load sqlite lazily not to require in start
* chore: add logging to calculate time for fetching
* feat: add converter from native code to SQLite
* feat: warn when sqlite.lua is not available
* feat: add FrecencyMigrateDB to migrate DB
* docs: add note for native code logic
* test: ignore type bug
