style: use postponed evaluation of annotations and update doctring style

[XuehaiPan]

Description

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Motivation and Context

Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.
You can use the syntax close #15213 if this solves the issue #15213

• I have raised an issue to propose this change (required for new features and bug fixes)

Use postponed evaluation of annotations and update doctring style.

Types of changes

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds core functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (update in the documentation)
• Example (update in the folder of example)

Checklist

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• I have read the CONTRIBUTION guide. (required)
• My change requires a change to the documentation.
• I have updated the tests accordingly. (required for a bug fix or a new feature)
• I have updated the documentation accordingly.
• I have reformatted the code using make format. (required)
• I have checked the code using make lint. (required)
• I have ensured make test pass. (required)

[Benjamin-eecs]

LGTM!

[codecov]

Codecov Report

Base: 91.73% // Head: 91.70% // Decreases project coverage by -0.03% ⚠️

Coverage data is based on head (905db2a) compared to base (c67476b).
Patch coverage: 99.28% of modified lines in pull request are covered.

❗ Current head 905db2a differs from pull request most recent head 00aba85. Consider uploading reports for the commit 00aba85 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #135      +/-   ##
==========================================
- Coverage   91.73%   91.70%   -0.03%     
==========================================
  Files          66       66              
  Lines        2551     2553       +2     
==========================================
+ Hits         2340     2341       +1     
- Misses        211      212       +1     

Flag	Coverage Δ
unittests	91.70% <99.28%> (-0.03%)	⬇️

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

Impacted Files	Coverage Δ
torchopt/alias/rmsprop.py	100.00% <ø> (ø)
torchopt/alias/sgd.py	100.00% <ø> (ø)
torchopt/optim/meta/rmsprop.py	90.00% <ø> (ø)
torchopt/optim/meta/sgd.py	88.89% <ø> (ø)
torchopt/optim/rmsprop.py	100.00% <ø> (ø)
torchopt/optim/sgd.py	100.00% <ø> (ø)
torchopt/schedule/polynomial.py	80.95% <ø> (ø)
torchopt/update.py	100.00% <ø> (ø)
torchopt/linalg/ns.py	41.38% <80.00%> (+1.72%)	⬆️
torchopt/accelerated_op/__init__.py	91.67% <100.00%> (-8.33%)	⬇️
... and 45 more

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