Add doc

(cherry picked from commit dd94863481555c22666a50a36b12ba2f9ae3798a)

IJ-MR-168243

GitOrigin-RevId: e681c5ed54c0cdf76460fd75aa3e76a502a59619

platform/lang-api/src/com/intellij/ide/actions/searcheverywhere/EssentialContributor.java

@@ -11,6 +11,12 @@ import org.jetbrains.annotations.Nullable;
  */
 public interface EssentialContributor {
 
+  /**
+   * Defines whether the contributor should be considered essential by default.
+   * This behavior may be altered by a machine learning model (the non-default behavior).
+   *
+   * @see EssentialContributor#checkEssential(SearchEverywhereContributor)
+   */
   default boolean isEssentialByDefault() {
     return true;
   }