Quickfix uses only simple filters

[som-snytt]

Reproduction steps

2.13.14

    //"-quickfix:cat=deprecation&msg=Auto-application",
    "-quickfix:msg=Auto-application",

Problem

The compound filter results in nothing applied, though specifying either cat or msg by itself works.

It is safer to specify the narrower compound filter.

Alternatively, the help text could be clearer about the limitation.

Alternatively, use syntax -Wconf:cat=deprecation&msg=Auto-application:qf since it is just another action.