Update src/core_codemods/docs/pixee_python_fix-dataclass-defaults.md

Co-authored-by: Dan D'Avella <[email protected]>

src/core_codemods/docs/pixee_python_fix-dataclass-defaults.md

@@ -1,4 +1,4 @@
-This codemod will fix instances of `dataclasses.dataclass` that define default lists, sets, or dicts which raise a runtime `ValueError`. The [dataclass documentation](https://docs.python.org/3/library/dataclasses.html#mutable-default-values) provides a clear explanation of why this code is disallowed and explains how to use `field(default_factory=...)` instead.
+When defining a Python dataclass it is not safe to use mutable datatypes (such as `list`, `dict`, or `set`) as defaults for the attributes. This is because the defined attribute will be shared by all instances of the dataclass type. Using such a mutable default will ultimately result in a `ValueError` at runtime. This codemod updates attributes of `dataclasses.dataclass` with mutable defaults to use `dataclasses.field` instead. The [dataclass documentation](https://docs.python.org/3/library/dataclasses.html#mutable-default-values) providesmore details about why using `field(default_factory=...)` is the recommended pattern.
 
 Our changes look something like this: