Format the README JIT example for ruff-format (#8785)

ruff-format 0.16.7 formats Python fences in Markdown and wants two
blank lines after a top-level function.

Assisted-by: Grok:4.6

README.md

@@ -166,6 +166,7 @@ def foo():
     a = 5
     return 10 + a
 
+
 foo.__jit__()  # this will compile foo to native code and subsequent calls will execute that native code
 assert foo() == 15
 ```