[Dynamo][Better Engineering] Add type coverage to decorators

[Lucaskabela]

As part of better engineering week, we would like to improve out type support to improve dev experience in dynamo

This PR adds strict typing support to an important file in dynamo, decorators.py

NOTE: Untyped fns are because there is a conflict with __init__.py in compiler so we can't type these at this time

Running

mypy torch/_dynamo/decorators.py --linecount-report /tmp/coverage_log

--------	Lines Unannotated	Lines Total	% lines covered	Funcs Unannotated	Funcs Total	% funcs covered
Main	209	908	23.02%	9	39	23.08%
This PR	870	943	100.00%	36	39	100.00%
Delta	+661	+35	+76.98%	+27	0	+76.92%

cc @voznesenskym @penguinwu @EikanWang @jgong5 @Guobing-Chen @XiaobingSuper @zhuhaozhe @blzheng @wenzhe-nrv @jiayisunx @chenyang78 @kadeng @chauhang @amjames

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/158509

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✅ You can merge normally! (1 Unrelated Failure)

As of commit 7daa01f with merge base 16b21fa ():

BROKEN TRUNK - The following job failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• inductor / cuda12.8-py3.10-gcc9-sm86 / test (inductor_torchbench, 1, 2, linux.g5.4xlarge.nvidia.gpu) (gh) (trunk failure)
  torchrec_dlrm

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[Lucaskabela]

@pytorchbot label "topic: not user facing"

[Lucaskabela]

@pytorchmergebot merge

[pytorchmergebot]

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[pytorchmergebot]

Merge failed

Reason: 1 jobs have failed, first few of them are: inductor / unit-test / cuda12.8-py3.12-gcc9-sm86 / build

Details for Dev Infra team

Raised by workflow job

[Lucaskabela]

@pytorchmergebot merge

[pytorchmergebot]

Merge started

Your change will be merged once all checks pass (ETA 0-4 Hours).

Learn more about merging in the wiki.

Questions? Feedback? Please reach out to the PyTorch DevX Team

Advanced Debugging

Check the merge workflow status
here