Doc: Fix parameter name typo in BertBackbone docstring (keras-team#2529)

* Doc: Fix parameter name typo in BertBackbone docstring

* Style: Apply Black and Isort formatting

* Style: Fix linting errors with Ruff

Author: jaytiwarihub

keras_hub/src/models/bert/bert_backbone.py

@@ -33,7 +33,7 @@ class BertBackbone(Backbone):
         vocabulary_size: int. The size of the token vocabulary.
         num_layers: int. The number of transformer layers.
         num_heads: int. The number of attention heads for each transformer.
-            The hidden size must be divisible by the number of attention heads.
+            The hidden_dim must be divisible by the number of attention heads.
         hidden_dim: int. The size of the transformer encoding and pooler layers.
         intermediate_dim: int. The output dimension of the first Dense layer in
             a two-layer feedforward network for each transformer.