Change IDEA codestyle href

[Persdre]

On the "Setting up and getting started" page of AB3 developer guide (https://nus-cs2103-ay2021s1.github.io/tp/SettingUp.html), the href for "[se-edu/guides] IDEA: Configuring the JDK" is pointed towards https://se-education.org/guides/tutorials/checkstyle.html, instead of https://se-education.org/guides/tutorials/intellijCodeStyle.html

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[codecov-commenter]

Codecov Report

Merging #50 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master      #50   +/-   ##
=========================================
  Coverage     72.31%   72.31%           
  Complexity      400      400           
=========================================
  Files            70       70           
  Lines          1228     1228           
  Branches        124      124           
=========================================
  Hits            888      888           
  Misses          308      308           
  Partials         32       32           

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[damithc]

Thanks for the fix @Persdre 💯