Consistently declare @⁠Nullable on parameter in equals() implementations

Closes gh-36075

Signed-off-by: 木葉 Scarlet <93977077+mukjepscarlet@users.noreply.github.com>

spring-aop/src/main/java/org/springframework/aop/framework/AdvisedSupport.java

@@ -731,7 +731,7 @@ public class AdvisedSupport extends ProxyConfig implements Advised {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			return (this == other || (other instanceof AdvisorKeyEntry that &&
 					this.adviceType == that.adviceType &&
 					ObjectUtils.nullSafeEquals(this.classFilterKey, that.classFilterKey) &&

spring-aop/src/main/java/org/springframework/aop/support/ClassFilters.java

@@ -198,7 +198,7 @@ public abstract class ClassFilters {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			return (this == other || (other instanceof NegateClassFilter that &&
 					this.original.equals(that.original)));
 		}

spring-aop/src/main/java/org/springframework/aop/support/MethodMatchers.java

@@ -378,7 +378,7 @@ public abstract class MethodMatchers {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			return (this == other || (other instanceof NegateMethodMatcher that &&
 					this.original.equals(that.original)));
 		}