tweak error messages

lib/alias.js

@@ -160,13 +160,13 @@ export default class Alias extends Now {
         const code = body.error.code;
 
         if ('custom_domain_needs_upgrade' === code) {
-          const err = new Error(`You are attempting to use a custom domain alias (${chalk.underline(chalk.cyan(alias))}), but this is only enabled for premium accounts. Please upgrade at ${chalk.underline('https://zeit.co/account')}`);
+          const err = new Error(`Custom domains are only enabled for premium accounts. Please upgrade at ${chalk.underline('https://zeit.co/account')}.`);
           err.userError = true;
           return bail(err);
         }
 
         if ('alias_in_use' === code) {
-          const err = new Error(`The alias you are trying to configure (${chalk.underline(chalk.cyan(alias))}) is already in use by a different account.`);
+          const err = new Error(`The alias you are trying to configure (${chalk.underline(chalk.bold(alias))}) is already in use by a different account.`);
           err.userError = true;
           return bail(err);
         }