Bug 1803543 - Improve the PreferenceRead marker schema to make the marker table show the name and value of the preferences, r=canaltinova.

Differential Revision: https://phabricator.services.mozilla.com/D163581

modules/libpref/Preferences.cpp

@@ -4623,6 +4623,9 @@ struct Internals {
       schema.AddKeyLabelFormat("prefKind", "Kind", MS::Format::String);
       schema.AddKeyLabelFormat("prefType", "Type", MS::Format::String);
       schema.AddKeyLabelFormat("prefValue", "Value", MS::Format::String);
+      schema.SetTableLabel(
+          "{marker.data.prefName}: {marker.data.prefValue} "
+          "({marker.data.prefType})");
       return schema;
     }