fix: Support single filters surrounded by parentheses

[claremacrae]

Background

I'm doing a lot of switching between pairs if similar queries, of which this is one example:

(not done) AND (happens before today)
not done

To switch between those, I have to:

1. Delete the ( and ) from (not done)
2. Append AND (happens before today)

Request

I would really like ( any valid filter ) to be equivalent to any valid filter.

For example, for (done) to work, instead of giving Tasks query: do not understand query: (done).

[claremacrae]

I've just merged a fix for this in #1170.
I'll update here when it's been released.

[claremacrae]

This has been released in Tasks 1.14.0.