Fixed typo in getStartIndex method in RocketMQ_Example.md file

[zfs9521]

Make sure set the target branch to develop

What is the purpose of the change

Fix RocketMQ_Example.md

Brief changelog

4.2消息列表分割示例 getStartIndex方法中变量名称错误

Verifying this change

messages.get(curIndex) -> messages.get(currIndex)

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[Kvicii]

LGTM

[caigy]

Please link this pr to related issue.

[codecov-commenter]

Codecov Report

Merging #4012 (2622ba3) into develop (b606d9c) will increase coverage by 0.12%.
The diff coverage is n/a.

❗ Current head 2622ba3 differs from pull request most recent head 525e21f. Consider uploading reports for the commit 525e21f to get more accurate results

@@              Coverage Diff              @@
##             develop    #4012      +/-   ##
=============================================
+ Coverage      47.53%   47.65%   +0.12%     
- Complexity      4931     4952      +21     
=============================================
  Files            633      633              
  Lines          42497    42497              
  Branches        5579     5579              
=============================================
+ Hits           20201    20252      +51     
+ Misses         19798    19753      -45     
+ Partials        2498     2492       -6     

Impacted Files	Coverage Δ
...ava/org/apache/rocketmq/test/util/VerifyUtils.java	46.26% <0.00%> (-2.99%)	⬇️
.../apache/rocketmq/logging/inner/LoggingBuilder.java	64.87% <0.00%> (+0.15%)	⬆️
...a/org/apache/rocketmq/store/StoreStatsService.java	30.61% <0.00%> (+0.65%)	⬆️
...he/rocketmq/client/trace/AsyncTraceDispatcher.java	81.18% <0.00%> (+1.48%)	⬆️
...e/rocketmq/remoting/netty/NettyRemotingClient.java	48.58% <0.00%> (+1.97%)	⬆️
...ava/org/apache/rocketmq/filter/util/BitsArray.java	62.39% <0.00%> (+2.56%)	⬆️
...pache/rocketmq/remoting/common/RemotingHelper.java	23.07% <0.00%> (+3.29%)	⬆️
...va/org/apache/rocketmq/common/stats/StatsItem.java	55.00% <0.00%> (+5.00%)	⬆️
.../apache/rocketmq/common/stats/MomentStatsItem.java	47.61% <0.00%> (+9.52%)	⬆️
...org/apache/rocketmq/common/stats/StatsItemSet.java	53.73% <0.00%> (+10.44%)	⬆️
... and 3 more

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