Remove use of outdated isempty(children(...)) pattern

[serenity4]

#661 was missing these two updates.

Fixes #673.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 0.00%. Comparing base (2c33b9a) to head (a2cb41f).
⚠️ Report is 83 commits behind head on master.

Files with missing lines	Patch %	Lines
src/codeview.jl	0.00%	2 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff           @@
##           master    #674   +/-   ##
======================================
  Coverage    0.00%   0.00%           
======================================
  Files           9      12    +3     
  Lines        1556    1600   +44     
======================================
- Misses       1556    1600   +44     

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