Refine missing InputBindResult

The SUCCESS_WITH_ACCESSIBILITY_SESSION result code
was introduced from CL[1].

-. Add the result code into getString() to avoid the
   unknown case.
-. Add comment for the result code.

[1]: Ia651a811093a939d00c081be1961e24ed3ad0356

Bug: 236920321
Test: presubmit
Change-Id: Ieb567237ad0a9cbde6eee47dbbd6c6609eb46688

core/java/com/android/internal/inputmethod/InputBindResult.java

@@ -170,6 +170,9 @@ public final class InputBindResult implements Parcelable {
          * display.
          */
         int ERROR_INVALID_DISPLAY_ID = 15;
+        /**
+         * Indicates that a valid session is created and result is ready for accessibility.
+         */
         int SUCCESS_WITH_ACCESSIBILITY_SESSION = 16;
     }
 
@@ -389,6 +392,8 @@ public final class InputBindResult implements Parcelable {
                 return "ERROR_DISPLAY_ID_MISMATCH";
             case ResultCode.ERROR_INVALID_DISPLAY_ID:
                 return "ERROR_INVALID_DISPLAY_ID";
+            case ResultCode.SUCCESS_WITH_ACCESSIBILITY_SESSION:
+                return "SUCCESS_WITH_ACCESSIBILITY_SESSION";
             default:
                 return "Unknown(" + result + ")";
         }