Add JA-JP reference guide

[shaydewael]

Summary

Adds the Japanese translation for the existing reference guide.

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

Merging #843 (c2c01c7) into main (ebc90bf) will not change coverage.
The diff coverage is n/a.

❗ Current head c2c01c7 differs from pull request most recent head 6dd3bcd. Consider uploading reports for the commit 6dd3bcd to get more accurate results

@@           Coverage Diff           @@
##             main     #843   +/-   ##
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  Coverage   65.89%   65.89%           
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  Files          13       13           
  Lines        1173     1173           
  Branches      343      343           
=======================================
  Hits          773      773           
  Misses        334      334           
  Partials       66       66           

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