Fix error in export example script (#8783)

Author: GregoryComer

docs/source/using-executorch-export.md

@@ -58,7 +58,7 @@ class Model(torch.nn.Module):
             torch.nn.ReLU(),
             torch.nn.Conv2d(8, 16, 3),
             torch.nn.ReLU(),
-            torch.nn.AdaptiveAvgPool2d([[1,1]])
+            torch.nn.AdaptiveAvgPool2d((1,1))
         )
         self.linear = torch.nn.Linear(16, 10)
 
@@ -175,4 +175,4 @@ For advanced use cases, see the following:
 - [Quantization Overview](quantization-overview.md) for information on quantizing models to reduce inference time and memory footprint.
 - [Memory Planning](compiler-memory-planning.md) for information on controlling memory placement and planning.
 - [Custom Compiler Passes](compiler-custom-compiler-passes.md) for information on writing custom compiler passes.
-- [Export IR Specification](ir-exir.md) for information on the intermediate representation generated by export.
+- [Export IR Specification](ir-exir.md) for information on the intermediate representation generated by export.