Warn when python files could override packages

[DonJayamanne]

For #7538

Todo:

• Wiki with information
• Ignore a specific file
• Disable this feature
• Tests
• Ignore files in Python environments (e.g if user opens a file that's in a Python env)
• Telemetry (whether users run into such issues, gives us an idea how many could potentially be crashing kernels due to such names)

[codecov-commenter]

Codecov Report

Merging #8727 (f7f21ab) into main (38162ee) will decrease coverage by 0%.
The diff coverage is 100%.

❗ Current head f7f21ab differs from pull request most recent head 13bf8f1. Consider uploading reports for the commit 13bf8f1 to get more accurate results

@@          Coverage Diff          @@
##            main   #8727   +/-   ##
=====================================
- Coverage     73%     73%   -1%     
=====================================
  Files        228     228           
  Lines      10491   10495    +4     
  Branches    1539    1539           
=====================================
- Hits        7702    7672   -30     
- Misses      2173    2203   +30     
- Partials     616     620    +4     

Impacted Files	Coverage Δ
src/platform/common/utils/localize.ts	96% <100%> (+<1%)	⬆️
src/platform/errors/sessionDisposedError.ts	60% <0%> (-40%)	⬇️
src/platform/commands/commandRegistry.ts	80% <0%> (-10%)	⬇️
src/platform/commands/serverSelector.ts	90% <0%> (-10%)	⬇️
src/platform/activation/activationManager.ts	56% <0%> (-5%)	⬇️
...m/common/variables/environmentVariablesProvider.ts	68% <0%> (-5%)	⬇️
...form/datascience/data-viewing/dataViewerFactory.ts	82% <0%> (-5%)	⬇️
src/platform/datascience/datascience.ts	92% <0%> (-4%)	⬇️
src/platform/common/process/baseDaemon.ts	32% <0%> (-4%)	⬇️
...c/platform/datascience/multiplexingDebugService.ts	52% <0%> (-4%)	⬇️
... and 7 more