Change heading size in Japanese locale

[t-hamano]

Partially addresses WordPress/wporg-main-2022#432

News-Single

• Specify font for h1 (Noto serif jp), font size 60px

Props @nukaga

This PR changes the size of Heading 1 from 70px to 60px in the Japanese locale. As far as I know, this change affects post titles and page titles.

Screenshots

Post

Before	After

Page

Header	Header

How to test the changes in this Pull Request:

If you would like to test this PR locally, follow the steps below.

• Create a folder source/wp-content/languages, with a themes folder inside.
• Download the attachment below, unzip it, and move it to the source/wp-content/languages/themes directory.
  wporg-ja.zip
• Create or open the file .wp-env.override.json
• Including the new language folder and main theme, map it as follows:

  {
  	"themes": [
  		"./source/wp-content/themes/wporg-parent-2021",
  		"./source/wp-content/themes/wporg-child-2021",
  		"../path/to/wporg-main-2022/source/wp-content/themes/wporg-main-2022"
  	],
  	"mappings": {
  		"env": "./env",
  		"wp-content/mu-plugins": "./source/wp-content/mu-plugins",
  		"wp-content/mu-plugins/0-sandbox.php": "./env/0-sandbox.php",
  		"wp-content/languages": "./source/wp-content/languages"
  	}
  }