simplify the wording of the MissingDefault summary

PiperOrigin-RevId: 853313727

Author: nanaze

core/src/main/java/com/google/errorprone/bugpatterns/MissingDefault.java

@@ -43,8 +43,8 @@
 @BugPattern(
     summary =
         "The Google Java Style Guide requires that each switch statement includes a default"
-            + " statement group, even if it contains no code. (This requirement is lifted for any"
-            + " switch statement that covers all values of an enum.)",
+            + " statement group (even if it contains no code) unless the switch statement "
+            + "covers all values of an enum.",
     severity = WARNING)
 public class MissingDefault extends BugChecker implements SwitchTreeMatcher {
   @Override