Include Documentation for Object Expression Syntax Construct

It would be useful for the N1QL Expressions documentation page to contain details regarding the Object Expression syntax construct.

For example, the below expression:

OBJECT o.f:o.v FOR o IN a1 END 

Where:

• The entity "f" is the unique name of the field string, which is either retrieved directly from the array "a1", or derived based on the position of the elements in the array
• The entity "v" is the correlating value for "f"

More details can be found in this Slack thread - https://couchbase.slack.com/archives/CD1R8GCRE/p1679513274068799