Update README.md - Annotator example (#261)

Add a package statement to the Annotator's expected input and output. Without it, if users copy the example directly, the class will not be recognized as annotated, and the Annotator will fail to infer any annotations. This update ensures consistency.

README.md

@@ -18,6 +18,7 @@ The final output of Annotator is a source code that passes NullAway checks with
 In the code below, `NullAway` reports five warnings.
 
 ```java
+package com.example;
 class Test{
     Object f1 = null; // warning: assigning @Nullable expression to @NonNull field
     Object f2 = null; // warning: assigning @Nullable expression to @NonNull field
@@ -49,6 +50,7 @@ For unresolved errors, suppression annotations are injected.
 The output below shows the result of running `Annotator` on the code above.
 
 ```java
+package com.example;
 import javax.annotation.Nullable; // added by Annotator
 import org.jspecify.annotations.NullUnmarked; // added by Annotator
 

sample/build.gradle

@@ -57,7 +57,7 @@ tasks.withType(JavaCompile).configureEach {
         options.errorprone {
             check("NullAway", CheckSeverity.ERROR)
             check("AnnotatorScanner", CheckSeverity.ERROR)
-            option("NullAway:AnnotatedPackages", "edu.ucr.cs.riple")
+            option("NullAway:AnnotatedPackages", "com.example")
             option("NullAway:SerializeFixMetadata", "true")
             option("NullAway:FixSerializationConfigPath", nullaway_config_path)
             option("AnnotatorScanner:ConfigPath", scanner_config_path)

sample/src/main/java/edu/ucr/cs/riple/annotator/sample/Test.java

@@ -22,7 +22,7 @@
  * THE SOFTWARE.
  */
 
-package edu.ucr.cs.riple.annotator.sample;
+package com.example;
 
 public class Test {
   Object f1 = null;