Add diagnostic hints to init timeout message

Add diagnostic hints to init timeout message

Expand the text in the init timeout message to give the reader more hints as to what may be causing the issue.

The current error sent me on a wild goose chase trying to debug my shortcodes, but it turned out that the issue was just that I wasn't caching my resources/ directory on my build server. Once I found this blog post, I solved the issue in minutes:

https://www.henriksommerfeld.se/hugo-timeout-not-a-circular-loop-in-shortcode/

Googling the error message yields several additional posts from users who focus on loops in their shortcode when the problem seems to be overly-expensive builds.