Match expressions Discrepancy between documentation and implementation

In the docs https://docs.influxdata.com/kapacitor/v1.5/working/alerts/#match-expressions it is mentioned " The data that triggered the alert is available to the match expression, including all fields and tags."

But in the implementation only tags are available for match and not fields
https://github.com/influxdata/kapacitor/blob/v1.5.6/services/alert/handlers.go#L531

Please acknowledge the bug and let me know if PR's are welcomed because I wanted to use fields in match expressions , especially previouslevel "PreviousLevel: e.previousState.Level"

Start by comparing the match-expression documentation with services/alert/handlers.go at line 531, where the issue reports that only tags are available. Trace how alert data reaches match expressions and determine the intended behavior for fields, including the requested PreviousLevel use. Done means the implementation matches the documented availability or the documentation clearly reflects the supported behavior.

Written by the indexing model from the issue text.