[PyTorch] Fix GQA error message (#1328)

* fix GQA error message
Signed-off-by: Charlene Yang <8636796+cyanguwa@users.noreply.github.com>

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci



---------
Signed-off-by: Charlene Yang <8636796+cyanguwa@users.noreply.github.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

transformer_engine/pytorch/attention.py

@@ -7952,7 +7952,10 @@ class DotProductAttention(TransformerEngineBaseModule):
             assert (
                 key_layer.shape[-2] == self.num_gqa_groups_per_partition
                 and value_layer.shape[-2] == self.num_gqa_groups_per_partition
-            ), f"Keys and values must have num_gqa_group = {self.num_gqa_groups} heads!"
+            ), (
+                "Keys and values must have num_gqa_group ="
+                f" {self.num_gqa_groups_per_partition} heads!"
+            )
             assert qkv_format in [
                 "sbhd",
                 "bshd",