Docs: update README (#50)

* Docs: update README

* Remove break lines

README.md

@@ -9,25 +9,19 @@ Adds useful decoration features to the Gutenberg RichText editor toolbar.
 
 ### Highlighter
 
-![Highlighter](https://github.com/t-hamano/richtext-extension/blob/images/highlighter_option.png)
+![Highlighter](https://raw.githubusercontent.com/t-hamano/richtext-extension/main/.wordpress-org/screenshot-4.png)
 
-![Highlighter](https://github.com/t-hamano/richtext-extension/blob/images/highlighter_editor.png)
+![Highlighter](https://raw.githubusercontent.com/t-hamano/richtext-extension/main/.wordpress-org/screenshot-1.png)
 
-Draw a marker on the inline text.
-
-You can set the color, thickness, and opacity of the marker to you can create various marker styles.
-
-Up to four types of settings can be made.
+Draw a marker on the inline text. You can set the color, thickness, and opacity of the marker to you can create various marker styles. Up to four types of settings can be made.
 
 ### Font size
 
-![Font size](https://github.com/t-hamano/richtext-extension/blob/images/fontsize_option.png)
-
-![Font size](https://github.com/t-hamano/richtext-extension/blob/images/fontsize_editor.png)
+![Font size](https://raw.githubusercontent.com/t-hamano/richtext-extension/main/.wordpress-org/screenshot-5.png)
 
-Change inline text size.
+![Font size](https://raw.githubusercontent.com/t-hamano/richtext-extension/main/.wordpress-org/screenshot-2.png)
 
-The size is specified as a percentage of the base font size, and up to four types of settings can be made.
+Change inline text size. The size is specified as a percentage of the base font size, and up to four types of settings can be made.
 
 ### Underline