[ISSUE #XXXX] Modify cn RocketMQ_Example.md

[yazong]

What is the purpose of the change

Symbol error in Chinese document

Brief changelog

XX

Verifying this change

XXXX

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[coveralls]

Coverage decreased (-0.04%) to 51.255% when pulling 51c9189 on yazong:master into 9f95a97 on apache:master.

[codecov-commenter]

Codecov Report

Merging #2299 into master will decrease coverage by 0.24%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #2299      +/-   ##
============================================
- Coverage     45.68%   45.43%   -0.25%     
+ Complexity     4269     4249      -20     
============================================
  Files           546      546              
  Lines         35860    35860              
  Branches       4763     4763              
============================================
- Hits          16381    16293      -88     
- Misses        17434    17516      +82     
- Partials       2045     2051       +6     

Impacted Files	Coverage Δ	Complexity Δ
...org/apache/rocketmq/common/stats/StatsItemSet.java	41.79% <0.00%> (-8.96%)	16.00% <0.00%> (-3.00%)
...ketmq/client/impl/consumer/PullMessageService.java	71.11% <0.00%> (-8.89%)	8.00% <0.00%> (-2.00%)
...org/apache/rocketmq/store/ha/WaitNotifyObject.java	75.00% <0.00%> (-7.70%)	10.00% <0.00%> (-1.00%)
...nt/impl/consumer/ConsumeMessageOrderlyService.java	38.98% <0.00%> (-6.50%)	16.00% <0.00%> (-3.00%)
...in/java/org/apache/rocketmq/test/util/MQAdmin.java	38.88% <0.00%> (-5.56%)	7.00% <0.00%> (-1.00%)
...ain/java/org/apache/rocketmq/test/util/MQWait.java	43.24% <0.00%> (-5.41%)	3.00% <0.00%> (ø%)
...he/rocketmq/client/impl/consumer/ProcessQueue.java	57.67% <0.00%> (-5.12%)	31.00% <0.00%> (-1.00%)
...e/rocketmq/client/impl/consumer/RebalanceImpl.java	50.99% <0.00%> (-4.39%)	34.00% <0.00%> (-2.00%)
...ache/rocketmq/common/stats/MomentStatsItemSet.java	39.13% <0.00%> (-4.35%)	5.00% <0.00%> (-1.00%)
...ava/org/apache/rocketmq/test/util/VerifyUtils.java	46.26% <0.00%> (-2.99%)	14.00% <0.00%> (-1.00%)
... and 10 more

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[RongtongJin]

@yazong Firstly, plz submit related issues to link this PR and explain the purpose of PR according to the format.
Second, you need change the target branch to develop.