Fix typoed artifact name in Lambda docs (Cherry-pick of #19739) (#19746)

Small typo in #19180: the target name is `lambda`, and hence the PEX
name will be `lambda.pex`, not `lambdex.pex`.

Co-authored-by: Huon Wilson <huon@exoflare.io>

docs/markdown/Python/python-integrations/awslambda-python.md

@@ -154,7 +154,7 @@ def example_handler(event, context):
     print("Hello AWS!")
 ```
 
-Then, use  `pants package project:lambda`, and upload the resulting `project/lambdex.pex` to AWS.  The handler will need to be configured in AWS as `__pex__.lambda_example.example_handler` (assuming `project` is a [source root](doc:source-roots)).
+Then, use  `pants package project:lambda`, and upload the resulting `project/lambda.pex` to AWS.  The handler will need to be configured in AWS as `__pex__.lambda_example.example_handler` (assuming `project` is a [source root](doc:source-roots)).
 
 Migrating from Pants 2.16 and earlier
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