Add CFComment for TemporalQuery and TemporalAccessor.

Author: cpovirk

src/java.base/share/classes/java/time/temporal/TemporalAccessor.java

@@ -63,6 +63,7 @@
 
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.checkerframework.framework.qual.AnnotatedFor;
+import org.checkerframework.framework.qual.CFComment;
 
 import java.time.DateTimeException;
 import java.util.Objects;
@@ -309,6 +310,8 @@ default int get(TemporalField field) {
      * @throws DateTimeException if unable to query
      * @throws ArithmeticException if numeric overflow occurs
      */
+    @CFComment({"nullness: TemporalQuery promises that this is equivalent to query.queryFrom, so "
+        + "it returns plain R, just like that method."})
     default <R> R query(TemporalQuery<R> query) {
         if (query == TemporalQueries.zoneId()
                 || query == TemporalQueries.chronology()

src/java.base/share/classes/java/time/temporal/TemporalQuery.java

@@ -62,6 +62,7 @@
 package java.time.temporal;
 
 import org.checkerframework.framework.qual.AnnotatedFor;
+import org.checkerframework.framework.qual.CFComment;
 
 import java.time.DateTimeException;
 
@@ -143,6 +144,8 @@ public interface TemporalQuery<R> {
      * @throws DateTimeException if unable to query
      * @throws ArithmeticException if numeric overflow occurs
      */
+    @CFComment({"nullness: This is a function object, so we return plain R to distinguish between "
+        + "instances that can return null and those that cannot."})
     R queryFrom(TemporalAccessor temporal);
 
 }