Update @AutoAnnotation documentation to say that it isn't needed in K…

…otlin.

RELNOTES=Update @AutoAnnotation documentation to say that it isn't needed in Kotlin.
PiperOrigin-RevId: 528617920

common/src/main/java/com/google/auto/common/Visibility.java

@@ -77,7 +77,7 @@ public static Visibility effectiveVisibilityOfElement(Element element) {
     Visibility effectiveVisibility = PUBLIC;
     Element currentElement = element;
     while (currentElement != null) {
-      // NOTE - because that requires Guava 30, which would
+      // NOTE: We don't use Guava's Comparators.min() because that requires Guava 30, which would
       // make this library unusable in annotation processors using Bazel < 5.0.
       effectiveVisibility = Ordering.natural().min(effectiveVisibility, ofElement(currentElement));
       currentElement = currentElement.getEnclosingElement();

value/src/main/java/com/google/auto/value/processor/TypeVariables.java

@@ -236,7 +236,7 @@ public TypeMirror visitArray(ArrayType t, Void p) {
         //    ImmutableSet<? extends T> target = ImmutableSet.copyOf(actualParameter);
         // We will infer E=<? extends T> and rewrite the formal parameter type to
         // <? extends T>[], which we must simplify to T[].
-        // TODO - returns null?
+        // TODO: what if getExtendsBound() returns null?
         comp = MoreTypes.asWildcard(comp).getExtendsBound();
       }
       return typeUtils.getArrayType(comp);

value/userguide/howto.md

@@ -292,6 +292,9 @@ good to go.
 
 ## <a name="annotation"></a>... use AutoValue to implement an annotation type?
 
+Note: If you are writing your annotation in Kotlin, you don't need to use
+`@AutoAnnotation`, since Kotlin allows you to instantiate annotations directly.
+
 Most users should never have the need to programmatically create "fake"
 annotation instances. But if you do, using `@AutoValue` in the usual way will
 fail because the `Annotation.hashCode` specification is incompatible with
@@ -315,28 +318,6 @@ public class Names {
 }
 ```
 
-In Java the method will usually be static. In Kotlin, which doesn't have static
-methods as such, a normal function can be used:
-
-```kotlin
-public class Names {
-  @AutoAnnotation public fun named(value: String): Named {
-    return AutoAnnotation_Names_named(value);
-  }
-}
-```
-
-Kotlin also allows you to instantiate annotations directly, so you may not need
-AutoAnnotation:
-
-```kotlin
-public class Names {
-  public fun named(value: String): Named {
-    return Named(value = value)
-  }
-}
-```
-
 If your annotation has several elements, you may prefer to use `@AutoBuilder`:
 
 ```java