[jvm-lang] add documentation for CreateFieldRequest

java/java-analysis-api/src/com/intellij/lang/jvm/actions/CreateFieldRequest.kt

@@ -19,13 +19,40 @@ import com.intellij.lang.jvm.JvmModifier
 
 interface CreateFieldRequest {
 
+  /**
+   * Request may be bound to the PSI-element in call-site language,
+   * which means request will become invalid if element is invalidated.
+   *
+   * @return `true` if it is safe to call other methods of this object, `false` otherwise
+   */
   val isValid: Boolean
 
+  /**
+   * @return name of the field to be created
+   */
   val fieldName: String
 
+  /**
+   * The common interface is not ready yet, so this is [Any]?.
+   * For Java language an array of [com.intellij.codeInsight.ExpectedTypeInfo] is returned now.
+   *
+   * @return expected type info of the field to be created
+   */
   val fieldType: Any?
 
+  /**
+   * Implementation are free to render any modifiers as long as they don't contradict with requested ones.
+   * Example: if constant field is requested then it will be rendered
+   *          with `static final` modifiers even if they are not present in this collection.
+   *
+   * @return modifiers that should be present when requested field is compiled
+   */
   val modifiers: Collection<JvmModifier>
 
+  /**
+   * Constant fields may be used in annotations and in other constant expressions.
+   *
+   * @return whether the field must be a compile-time constant
+   */
   val constant: Boolean
 }