Search Extensions: support custom note title

The problem

When a plugin creates a note with search results, it uses search terms as the note title.

Now, if afterwards I rename the note (to be more descriptive) and then click "refresh" link in the note, it creates a new note with fresh search results instead of updating the existing one (obviously, because it is looking for a note with a corresponding name).

Proposed solution

Allow user to optionally specify custom note title when he or she is performing the search (new input in the UI of /flexiSearch would be absolutely enough for me personally, although some other users who use the plugin commands without the UI might want an optional parameter support as well).

This way one still won't be able to change the note title after search results note has been created, but at least one would be able to set the title before creating that note.

Inizia dalla UI /flexiSearch e segui come vengono create e successivamente aggiornate le note dei risultati di ricerca. Verifica se il percorso del comando del plugin è separato, quindi verifica che un titolo personalizzato opzionale venga preservato, in modo che l'aggiornamento modifichi la nota esistente invece di crearne una nuova.