Minimal adjustments to the short description (#18001)

Minimal adjustments have been made to the short description so that it logically follows the long description

lib/mastodon/accounts_cli.rb

@@ -57,7 +57,7 @@ module Mastodon
     option :role
     option :reattach, type: :boolean
     option :force, type: :boolean
-    desc 'create USERNAME', 'Create a new user'
+    desc 'create USERNAME', 'Create a new user account'
     long_desc <<-LONG_DESC
       Create a new user account with a given USERNAME and an
       e-mail address provided with --email.
@@ -133,7 +133,7 @@ module Mastodon
     option :disable_2fa, type: :boolean
     option :approve, type: :boolean
     option :reset_password, type: :boolean
-    desc 'modify USERNAME', 'Modify a user'
+    desc 'modify USERNAME', 'Modify a user account'
     long_desc <<-LONG_DESC
       Modify a user account.