[fix] [doc] Fix outdated java-doc of rate limiter (#19014)

### Motivation
After PR #8611, the acquiring permits can be larger than configured msg-rate if used by subscribing. But doc was not updated in time.

### Modifications

fix the outdated doc

pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/DispatchRateLimiter.java

@@ -99,10 +99,8 @@ public long getAvailableDispatchRateLimitOnByte() {
      */
     public boolean tryDispatchPermit(long msgPermits, long bytePermits) {
         boolean acquiredMsgPermit = msgPermits <= 0 || dispatchRateLimiterOnMessage == null
-        // acquiring permits must be < configured msg-rate;
                 || dispatchRateLimiterOnMessage.tryAcquire(msgPermits);
         boolean acquiredBytePermit = bytePermits <= 0 || dispatchRateLimiterOnByte == null
-        // acquiring permits must be < configured msg-rate;
                 || dispatchRateLimiterOnByte.tryAcquire(bytePermits);
         return acquiredMsgPermit && acquiredBytePermit;
     }