Kotlin 2.4.0: Address peer review

* Update documentation to only claim support for 2.4.0x
* Python test code; remove newlines between imports.
* Sync comments between kotlin 1.8 and 1.9
* Update code comments to attach where actually relevant,
  and improve comments on IrMemberAccessExpression<*>.extensionReceiverParameterIndex()

java/ql/integration-tests/kotlin/all-platforms/enhanced-nullability/test.py

@@ -1,5 +1,4 @@
 import pathlib
-
 import pytest
 
 

java/ql/integration-tests/kotlin/all-platforms/external-property-overloads/test.py

@@ -1,5 +1,4 @@
 import commands
-
 import pytest
 
 

java/ql/integration-tests/kotlin/all-platforms/file_classes/test.py

@@ -1,5 +1,4 @@
 import commands
-
 import pytest
 
 

java/ql/integration-tests/kotlin/all-platforms/java-interface-redeclares-tostring/test.py

@@ -1,5 +1,4 @@
 import commands
-
 import pytest
 
 

java/ql/integration-tests/kotlin/all-platforms/kotlin_java_lowering_wildcards/test.py

@@ -1,5 +1,4 @@
 import commands
-
 import pytest