Fix empty <p> tag warning in o/e/m/o/OsProbe.java

This commit fixes an empty <p> tag warning in o/e/m/o/OsProbe.java.

core/src/main/java/org/elasticsearch/monitor/os/OsProbe.java

@@ -399,13 +399,11 @@ public class OsProbe {
      * group to which the Elasticsearch process belongs for the
      * {@code cpu} subsystem. These lines represent the CPU time
      * statistics and have the form
-     * <p>
-     * <pre>
+     * <blockquote><pre>
      * nr_periods \d+
      * nr_throttled \d+
      * throttled_time \d+
-     * </pre>
-     * <p>
+     * </pre></blockquote>
      * where {@code nr_periods} is the number of period intervals
      * as specified by {@code cpu.cfs_period_us} that have elapsed,
      * {@code nr_throttled} is the number of times tasks in the given