add table to migration guide

Author: janis-bhm

release-content/migration-guides/combinator_system.md

@@ -4,7 +4,20 @@ pull_requests: [20671]
 ---
 
 The `CombinatorSystem`s can be used to combine multiple `SystemCondition`s with logical operators. Previously, the conditions would short circuit if the system failed to run, for example because it's query could not be filled by the world.
-Now, if a `SystemCondition` fails, it will be considered to have returned `false` and in combinators that don't short circuit the other condition will now be run.
+
+Now, the `CombinatorSystem`s will work as expected, following the semantics of rust's logical operators.
+Namely, if a `SystemCondition` fails, it will be considered to have returned `false` and in combinators that don't short circuit the other condition will now be run.
+
+Specifically, the combinators act as follows:
+
+| Combinator | Rust Equivalent |
+|:----------:|:---------------:|
+| `and`      | `a && b`        |
+| `or`       | `a || b`        |
+| `xor`      | `a ^ b`         |
+| `nand`     | `!(a && b)`     |
+| `nor`      | `!(a || b)`     |
+| `xnor`     | `!(a ^ b)`      |
 
 ```rust
 fn vacant(_: crate::system::Single<&Vacant>) -> bool {