docs: illustrate nursery.start service readiness

[tonyzedginidze]

Hi, let me know if something like this is allowed. If no mention of svg website preferred, its fine I can also remove.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00000%. Comparing base (bcc9cee) to head (82fadab).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@               Coverage Diff               @@
##                 main        #3540   +/-   ##
===============================================
  Coverage   100.00000%   100.00000%           
===============================================
  Files             128          128           
  Lines           19474        19474           
  Branches         1323         1323           
===============================================
  Hits            19474        19474           

see 2 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[A5rocks]

Sorry, I'm not convinced this helps explain the concept in the docs!