Extend bad-dunder-method-name to permit attrs dunders (#7472)

## Summary

Closes #7451.

## Test Plan

`cargo test`

crates/ruff/resources/test/fixtures/pylint/bad_dunder_method_name.py

@@ -49,6 +49,16 @@ def __private_method(self):
     def __doc__(self):
         return "Docstring"
 
+    # Allow dunder methods recommended by attrs.
+    def __attrs_post_init__(self):
+        pass
+
+    def __attrs_pre_init__(self):
+        pass
+
+    def __attrs_init__(self):
+        pass
+
 
 def __foo_bar__():  # this is not checked by the [bad-dunder-name] rule
     ...

crates/ruff/src/rules/pylint/rules/bad_dunder_method_name.rs

@@ -83,6 +83,9 @@ fn is_known_dunder_method(method: &str) -> bool {
             | "__aiter__"
             | "__and__"
             | "__anext__"
+            | "__attrs_init__"
+            | "__attrs_post_init__"
+            | "__attrs_pre_init__"
             | "__await__"
             | "__bool__"
             | "__bytes__"