fix: C# EvalRule (#387)

- Fix EvalRule to call EvalRule instead of EvalQuery
- Also fix clippy errors

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

bindings/csharp/Regorus/Regorus.cs

@@ -168,7 +168,7 @@ namespace Regorus
             var ruleBytes = NullTerminatedUTF8Bytes(rule);
             fixed (byte* rulePtr = ruleBytes)
             {
-                return CheckAndDropResult(Regorus.Internal.API.regorus_engine_eval_query(E, rulePtr));
+                return CheckAndDropResult(Regorus.Internal.API.regorus_engine_eval_rule(E, rulePtr));
             }
         }