Twenty Nineteen: Update theme description and tags.

The original theme description in Twenty Nineteen was intended as a placeholder; this update replaces it with a proper description, and removes the unnecessary `theme-options` tag. 

Props jobthomas, kjellr.
Merges [44377] to the 5.0 branch.
Fixes #45693.

git-svn-id: https://develop.svn.wordpress.org/branches/5.0@44429 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-content/themes/twentynineteen/readme.txt

@@ -1,6 +1,6 @@
 === Twenty Nineteen ===
 Contributors: the WordPress team
-Tags: one-column, flexible-header, accessibility-ready, custom-colors, custom-menu, custom-logo, editor-style, featured-images, footer-widgets, rtl-language-support, sticky-post, theme-options, threaded-comments, translation-ready
+Tags: one-column, flexible-header, accessibility-ready, custom-colors, custom-menu, custom-logo, editor-style, featured-images, footer-widgets, rtl-language-support, sticky-post, threaded-comments, translation-ready
 Requires at least: 4.9.6
 Tested up to: WordPress 5.0
 Stable tag: 1.1

src/wp-content/themes/twentynineteen/style-rtl.css

@@ -4,13 +4,13 @@ Theme Name: Twenty Nineteen
 Theme URI: https://github.com/WordPress/twentynineteen
 Author: the WordPress team
 Author URI: https://wordpress.org/
-Description: A new Gutenberg-ready theme.
+Description: Our 2019 default theme is designed to show off the power of the block editor. It features custom styles for all the default blocks, and is built so that what you see in the editor looks like what you'll see on your website. Twenty Nineteen is designed to be adaptable to a wide range of websites, whether you’re running a photo blog, launching a new business, or supporting a non-profit. Featuring ample whitespace and modern sans-serif headlines paired with classic serif body text, it's built to be beautiful on all screen sizes.
 Requires at least: WordPress 4.9.6
 Version: 1.0
 License: GNU General Public License v2 or later
 License URI: LICENSE
 Text Domain: twentynineteen
-Tags: custom-background, custom-logo, custom-menu, featured-images, threaded-comments, translation-ready
+Tags: one-column, flexible-header, accessibility-ready, custom-colors, custom-menu, custom-logo, editor-style, featured-images, footer-widgets, rtl-language-support, sticky-post, threaded-comments, translation-ready
 
 This theme, like WordPress, is licensed under the GPL.
 Use it to make something cool, have fun, and share what you've learned with others.

src/wp-content/themes/twentynineteen/style.css

@@ -4,13 +4,13 @@ Theme Name: Twenty Nineteen
 Theme URI: https://github.com/WordPress/twentynineteen
 Author: the WordPress team
 Author URI: https://wordpress.org/
-Description: A new Gutenberg-ready theme.
+Description: Our 2019 default theme is designed to show off the power of the block editor. It features custom styles for all the default blocks, and is built so that what you see in the editor looks like what you'll see on your website. Twenty Nineteen is designed to be adaptable to a wide range of websites, whether you’re running a photo blog, launching a new business, or supporting a non-profit. Featuring ample whitespace and modern sans-serif headlines paired with classic serif body text, it's built to be beautiful on all screen sizes.
 Requires at least: WordPress 4.9.6
 Version: 1.1
 License: GNU General Public License v2 or later
 License URI: LICENSE
 Text Domain: twentynineteen
-Tags: custom-background, custom-logo, custom-menu, featured-images, threaded-comments, translation-ready
+Tags: one-column, flexible-header, accessibility-ready, custom-colors, custom-menu, custom-logo, editor-style, featured-images, footer-widgets, rtl-language-support, sticky-post, threaded-comments, translation-ready
 
 This theme, like WordPress, is licensed under the GPL.
 Use it to make something cool, have fun, and share what you've learned with others.

src/wp-content/themes/twentynineteen/style.scss

@@ -3,13 +3,13 @@ Theme Name: Twenty Nineteen
 Theme URI: https://github.com/WordPress/twentynineteen
 Author: the WordPress team
 Author URI: https://wordpress.org/
-Description: A new Gutenberg-ready theme.
+Description: Our 2019 default theme is designed to show off the power of the block editor. It features custom styles for all the default blocks, and is built so that what you see in the editor looks like what you'll see on your website. Twenty Nineteen is designed to be adaptable to a wide range of websites, whether you’re running a photo blog, launching a new business, or supporting a non-profit. Featuring ample whitespace and modern sans-serif headlines paired with classic serif body text, it's built to be beautiful on all screen sizes.
 Requires at least: WordPress 4.9.6
 Version: 1.1
 License: GNU General Public License v2 or later
 License URI: LICENSE
 Text Domain: twentynineteen
-Tags: custom-background, custom-logo, custom-menu, featured-images, threaded-comments, translation-ready
+Tags: one-column, flexible-header, accessibility-ready, custom-colors, custom-menu, custom-logo, editor-style, featured-images, footer-widgets, rtl-language-support, sticky-post, threaded-comments, translation-ready
 
 This theme, like WordPress, is licensed under the GPL.
 Use it to make something cool, have fun, and share what you've learned with others.