add the parent node to "__main__"

[temyurchenko]

Not having a parent leads to weird situations, like root() returning
the node itself, not a Module.

Type of Changes

	Type
✓	🐛 Bug fix

[temyurchenko]

split out of #2536

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.98%. Comparing base (78f7f60) to head (02fa714).
Report is 12 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2551      +/-   ##
==========================================
- Coverage   92.98%   92.98%   -0.01%     
==========================================
  Files          93       93              
  Lines       11048    11083      +35     
==========================================
+ Hits        10273    10305      +32     
- Misses        775      778       +3     

Flag	Coverage Δ
linux	92.86% <100.00%> (+<0.01%)	⬆️
pypy	92.98% <100.00%> (-0.01%)	⬇️
windows	92.96% <100.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
astroid/nodes/scoped_nodes/scoped_nodes.py	92.80% <100.00%> (+0.01%)	⬆️

... and 37 files with indirect coverage changes