Specify scope options in same format as other arguments that have a list (#321)

Author: janw-me

src/DB_Command.php

@@ -957,7 +957,22 @@ public function import( $args, $assoc_args ) {
 	 * : List tables based on wildcard search, e.g. 'wp_*_options' or 'wp_post?'.
 	 *
 	 * [--scope=<scope>]
-	 * : Can be all, global, ms_global, blog, or old tables. Defaults to all.
+	 * : List tables based on the scope.
+	 *
+	 * - all: returns 'all' and 'global' tables. No old tables are returned.
+	 * - blog: returns the blog-level tables for the queried blog.
+	 * - global: returns the global tables for the installation, returning multisite tables only on multisite.
+	 * - ms_global: returns the multisite global tables, regardless if current installation is multisite.
+	 * - old: returns tables which are deprecated.
+	 * ---
+	 * default: all
+	 * options:
+	 *   - all
+	 *   - blog
+	 *   - global
+	 *   - ms_global
+	 *   - old
+	 * ---
 	 *
 	 * [--network]
 	 * : List all the tables in a multisite install.