Add code folding regions for # %% cells within python files

[amunger]

fixes #1527

re-use the ranges that the codelense provider is already calculating

[DonJayamanne]

I'd change this to register the providers like in PythonKernelCompletionProviderRegistration

[codecov-commenter]

Codecov Report

Merging #11418 (8f4e999) into main (2d32b19) will increase coverage by 0%.
The diff coverage is 81%.

❗ Current head 8f4e999 differs from pull request most recent head a5777cf. Consider uploading reports for the commit a5777cf to get more accurate results

@@          Coverage Diff           @@
##            main   #11418   +/-   ##
======================================
  Coverage     63%      63%           
======================================
  Files        476      477    +1     
  Lines      33951    33983   +32     
  Branches    5506     5509    +3     
======================================
+ Hits       21540    21578   +38     
+ Misses     10355    10346    -9     
- Partials    2056     2059    +3     

Impacted Files	Coverage Δ
...ow/editor-integration/pythonCellFoldingProvider.ts	73% <73%> (ø)
src/interactive-window/editor-integration/types.ts	100% <100%> (ø)
src/interactive-window/serviceRegistry.node.ts	100% <100%> (ø)
src/standalone/activation/globalActivation.ts	90% <100%> (+<1%)	⬆️
...kernels/jupyter/preferredRemoteKernelIdProvider.ts	85% <0%> (-8%)	⬇️
src/kernels/helpers.ts	66% <0%> (-2%)	⬇️
src/platform/msrCrypto/msrCrypto.js	19% <0%> (-1%)	⬇️
src/standalone/import-export/importTracker.node.ts
...s/jupyter/jupyterCellOutputMimeTypeTracker.node.ts
src/standalone/import-export/importTracker.ts	87% <0%> (ø)
... and 9 more

[rgbmrc]

Is it possible to disable this? I am afraid it messes with preexisting # region blocks.

[amunger]

@rgbmrc - the pre-release version has a jupyter.pythonCellFolding setting, and it should be available in release next week