Restore import for java.util.Formatter.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=108345794

guava/src/com/google/common/base/Strings.java

@@ -22,6 +22,8 @@
 import com.google.common.annotations.GwtCompatible;
 import com.google.common.annotations.VisibleForTesting;
 
+import java.util.Formatter;
+
 import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 
@@ -86,7 +88,7 @@ public static boolean isNullOrEmpty(@Nullable String string) {
    * <li>{@code padStart("2010", 3, '0')} returns {@code "2010"}
    * </ul>
    *
-   * <p>See {@link java.util.Formatter} for a richer set of formatting capabilities.
+   * <p>See {@link Formatter} for a richer set of formatting capabilities.
    *
    * @param string the string which should appear at the end of the result
    * @param minLength the minimum length the resulting string must have. Can be
@@ -118,7 +120,7 @@ public static String padStart(String string, int minLength, char padChar) {
    * <li>{@code padEnd("2010", 3, '!')} returns {@code "2010"}
    * </ul>
    *
-   * <p>See {@link java.util.Formatter} for a richer set of formatting capabilities.
+   * <p>See {@link Formatter} for a richer set of formatting capabilities.
    *
    * @param string the string which should appear at the beginning of the result
    * @param minLength the minimum length the resulting string must have. Can be