Document Environment::local() in xp lambda run vs xp lambda test

Author: thekid

README.md

@@ -92,7 +92,7 @@ $ xp lambda run Greet '{"name":"Timm"}'
 Hello Timm from PHP 8.2.7 via Greet @ test-local-1
 ```
 
-*This does not provide a complete lambda environment, and does not have any execution limits imposed on it!*
+*This does not provide a complete lambda environment, and does not have any execution limits imposed on it! To detect this programmatically, use `$this->environment->local()`, which will return true.*
 
 Integration testing
 -------------------
@@ -106,7 +106,7 @@ REPORT RequestId: 9ff45cda-df9b-1b8c-c21b-5fe27c8f2d24  Init Duration: 922.19 ms
 "Hello Timm from PHP 8.2.7 via test @ us-east-1"
 ```
 
-*This functionality is provided by the [AWS Lambda base images for custom runtimes](https://gallery.ecr.aws/lambda/provided)*
+*This functionality is provided by the [AWS Lambda base images for custom runtimes](https://gallery.ecr.aws/lambda/provided). Although this also runs on your machine, `$this->environment->local()` will return false.*
 
 Setup
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