General: Improve terminology used when referring to installations of WordPress and its extensions.

"Install" is not a noun, and while it might be acceptable to use the verb as a noun, it is not correct. Using the correct
noun, "installation", increases clarity, especially for non-native English speakers.

This change fixes the usage in user-facing text and in developer documentation.

Fixes #41620


git-svn-id: https://develop.svn.wordpress.org/trunk@41289 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/script-loader.php

@@ -743,7 +743,7 @@ function wp_default_scripts( &$scripts ) {
 				'installing'                 => __( 'Installing...' ),
 				'pluginInstalled'            => _x( 'Installed!', 'plugin' ),
 				'themeInstalled'             => _x( 'Installed!', 'theme' ),
-				'installFailedShort'         => __( 'Install Failed!' ),
+				'installFailedShort'         => __( 'Installation Failed!' ),
 				/* translators: %s: Error string for a failed installation */
 				'installFailed'              => __( 'Installation failed: %s' ),
 				/* translators: %s: Plugin name and version */