Use literal constant for QuotingType in csv Module

[max-muoto]

The mentioned moratorium is long over (#7258), and similar literals constants are commonly used in TypeShed at this point. Unless there's a major point of objection, and the fact that in most cases the constants are being directly passed into csv.writer(...) the chance of false positives is pretty low.

[srittau]

Thanks, some projects will need to update their annotations, but that's acceptable to me. But in general we only add tests for complex annotations. These annotations look straight forward enough for me that we don't need tests.

[max-muoto]

Thanks, some projects will need to update their annotations, but that's acceptable to me. But in general we only add tests for complex annotations. These annotations look straight forward enough for me that we don't need tests.

Removed: 95d040d

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

pandas (https://github.com/pandas-dev/pandas)
+ pandas/io/formats/csvs.py:264: error: Argument "quoting" to "writer" has incompatible type "int"; expected "Literal[0, 1, 2, 3]"  [arg-type]

static-frame (https://github.com/static-frame/static-frame)
+ static_frame/core/frame.py:9096: error: Argument "quoting" to "writer" has incompatible type "int"; expected "Literal[0, 1, 2, 3, 4, 5]"  [arg-type]