JA text edited

[stanleyneko]

Changes in this pull request:

• adding SVG icons tutorials are missing
• updated the unmatched codes from the EN tutorial

closes #1811

[das-g]

Thank you for this contribution. If you haven't already, can you also make the corresponding changes on https://crowdin.com/project/django-girls-tutorial ? That's where we manage the translations of the tutorial, to make it easier to see what needs re-translation when the English original changes.

[stanleyneko]

Hi, sure. I have not changed crowdin. so I am doing now :).

[stanleyneko]

I have looked through the texts and actually the all issue I raised in the Django Forms have been updated already on Crowdin. So I did not change any texts there!