require comment explaining `type: ignore` comments

incorrect:
```py
def foo():
a: str = 1 # type: ignore[assignment] # error: add a comment on the line above explaining why the error is being ignored
```

correct:
```py
def foo():
# false positive, see https://github.com/KotlinIsland/basedmypy/issues/252
a: str = 1 # type: ignore[assignment]
```

eslint has a rule for this: https://typescript-eslint.io/rules/ban-ts-comment/

Start by locating the handling of `# type: ignore` comments and review the issue’s incorrect and correct examples alongside the linked ESLint rule. Done means an ignored error requires an explanatory comment on the preceding line, while the documented valid form remains accepted.

Written by the indexing model from the issue text.