Change _get_assign_nodes() to cached_property

[jacobtylerwalls]

Type of Changes

	Type
✓	🐛 Bug fix

Description

cached_property does a much better job cleaning up after itself than we're doing.

Refs #1780

[DanielNoord]

Pehaps out of scope, but this seems to indicate that this returns list[nodes.Assign]? Perhaps nice to add as well?

Anyway, I feel like the name doesn't really do the property justice anymore. What about something like _assign_nodes_in_scope?

[codecov]

Codecov Report

Merging #2051 (dcd6a69) into main (c752c33) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2051      +/-   ##
==========================================
- Coverage   92.82%   92.82%   -0.01%     
==========================================
  Files          95       95              
  Lines       11066    11065       -1     
==========================================
- Hits        10272    10271       -1     
  Misses        794      794              

Flag	Coverage Δ
linux	92.54% <100.00%> (-0.01%)	⬇️
pypy	88.16% <100.00%> (-0.01%)	⬇️
windows	92.38% <100.00%> (-0.01%)	⬇️

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

Impacted Files	Coverage Δ
astroid/nodes/_base_nodes.py	98.14% <100.00%> (-0.02%)	⬇️
astroid/nodes/node_classes.py	95.05% <100.00%> (ø)
astroid/nodes/node_ng.py	93.07% <100.00%> (ø)
astroid/nodes/scoped_nodes/scoped_nodes.py	93.07% <100.00%> (ø)