clp-s: Use standard syntax for conditions on values between ()

[gibber9809]

Request

We currently support a non-standard syntax for combining filters on many values for the same column. A query like key: (value1 or value2) in KQL can be written as key: (OR value1 value2) in our syntax. This breaks the expectations of users familiar with KQL, so we should change the syntax to match.

Possible implementation

Update the grammar to match standard KQL behaviour for this case.