Compiler issue fix

metadata/src/main/java/com/google/i18n/phonenumbers/metadata/model/FormatSpec.java

diff --git a/metadata/src/main/java/com/google/i18n/phonenumbers/metadata/model/FormatSpec.java b/metadata/src/main/java/com/google/i18n/phonenumbers/metadata/model/FormatSpec.java
index 7ab9dfe..1ad11c6 100644
--- a/metadata/src/main/java/com/google/i18n/phonenumbers/metadata/model/FormatSpec.java
+++ b/metadata/src/main/java/com/google/i18n/phonenumbers/metadata/model/FormatSpec.java
@@ -620,7 +620,7 @@
     @Override
     public final String toString() {
       String group =
-          "X".repeat(minLength()) + "*".Strings.repeat(maxLength() - minLength());
+          "X".repeat(minLength()) + "*".repeat(maxLength() - minLength());
       return replacement().map(r -> String.format("{%s>%s}", group, r)).orElse(group);
     }
   }