Remove reference to `/* That’s all, stop editing! Happy publishing. */` line

[jazzsequence]

The multisite setup instructions say to add the multisite config above the /* That’s all, stop editing! Happy publishing. */ line in the config/application.php file.

However, this file does not have that line. This should be updated to use a different marker (like above the Config::apply() line or above the $env_config ... line.

This would need to be added to the filter that already exists to change the network setup page.

Blocked by pantheon-systems/pantheon-mu-plugin#55

[jazzsequence]

The existing filter only applies to the configuration code, not the full text of this screen. No filter currently exists for the rest of the content on the page. Created pantheon-systems/pantheon-mu-plugin#55 to fix this in the mu-plugin first.