Moved Query into separate actions.

src/document/field.rs

@@ -435,6 +435,10 @@ impl Revision {
     fn new() -> Self {
         Self {}
     }
+
+    fn revision(&self) -> isize {
+        0
+    }
 }
 
 #[cfg(test)]
@@ -444,5 +448,6 @@ mod revisions {
     #[test]
     fn can_create_empty_revision() {
         let rev = Revision::new();
+        assert_eq!(rev.revision(), 0);
     }
 }