Add known problems warning to type-comparison rule (#12769)

## Summary

See: #4560

crates/ruff_linter/src/rules/pycodestyle/rules/type_comparison.rs

@@ -18,6 +18,22 @@ use crate::checkers::ast::Checker;
 ///
 /// If you want to check for an exact type match, use `is` or `is not`.
 ///
+/// ## Known problems
+/// When using libraries that override the `==` (`__eq__`) operator (such as NumPy,
+/// Pandas, and SQLAlchemy), this rule may produce false positives, as converting
+/// from `==` to `is` or `is not` will change the behavior of the code.
+///
+/// For example, the following operations are _not_ equivalent:
+/// ```python
+/// import numpy as np
+///
+/// np.array([True, False]) == False
+/// # array([False,  True])
+///
+/// np.array([True, False]) is False
+/// # False
+/// ```
+///
 /// ## Example
 /// ```python
 /// if type(obj) == type(1):