C#: Add change note

Author: hvitved

change-notes/1.18/analysis-csharp.md

@@ -15,8 +15,11 @@
 
 | **Query**                   | **Tags**  | **Purpose**                                                        |
 |-----------------------------|-----------|--------------------------------------------------------------------|
-| [Exposing internal representation (cs/expose-implementation)] | Different results | The query has been rewritten, based on the equivalent Java query. |
+| Constant condition (cs/constant-condition) | More results | The query has been generalized to cover both `Null-coalescing left operand is constant (cs/constant-null-coalescing)` and `Switch selector is constant (cs/constant-switch-selector)`. |
+| Exposing internal representation (cs/expose-implementation) | Different results | The query has been rewritten, based on the equivalent Java query. |
 | Local scope variable shadows member (cs/local-shadows-member) | maintainability, readability | Replaces the existing queries [Local variable shadows class member (cs/local-shadows-class-member)](https://help.semmle.com/wiki/display/CSHARP/Local+variable+shadows+class+member), [Local variable shadows struct member (cs/local-shadows-struct-member)](https://help.semmle.com/wiki/display/CSHARP/Local+variable+shadows+struct+member), [Parameter shadows class member (cs/parameter-shadows-class-member)](https://help.semmle.com/wiki/display/CSHARP/Parameter+shadows+class+member), and [Parameter shadows struct member (cs/parameter-shadows-struct-member)](https://help.semmle.com/wiki/display/CSHARP/Parameter+shadows+struct+member). |
+| Null-coalescing left operand is constant (cs/constant-null-coalescing) | No results | The query has been removed, as it is now covered by `Constant condition (cs/constant-condition)`. |
+| Switch selector is constant (cs/constant-switch-selector) | No results | The query has been removed, as it is now covered by `Constant condition (cs/constant-condition)`. |
 
 ## Changes to existing queries