Fix typos and grammatical errors in comments and docstrings (#194322)

Corrects grammar mistakes, duplicated words, and typos across comments,
docstrings, and documentation in torch/. No functional changes; only
comment and docstring text is modified.

Notable fixes beyond simple grammar: the `_traceback.py` comment referred
to a nonexistent `co_firstfileno` attribute where the code actually copies
`co_firstlineno`, and the `SummaryWriter.add_graph` docstring for
`walltime` had a mangled fragment (`_get_file_writerfrom time.time())`)
that is now a readable description.

Test Plan: no code changes, so behavior is unaffected. Verified the docs
still render and lint passes:

```
lintrunner -a
```

This change was authored with the assistance of an AI coding assistant.

Pull Request resolved: https://github.com/pytorch/pytorch/pull/194322
Approved by: https://github.com/aorenste