Fix the markdown URL in the sample notebook

URLs without `https://` are relative.

wasm/notebook/snippets/python-markdown-math.txt

@@ -20,7 +20,7 @@ In the notebook, you can write markdown, math and python. use %% then:
 
 
 I **can** bold things and _italicize_ them. You got the gist, this is standard
-markdown syntax that you can [google](google.com).
+markdown syntax that you can [google](https://google.com).
 
 <br>
 
@@ -66,4 +66,4 @@ print("RustPython called back and said people need to have")
 import random 
 rnd = random.randint(1,5)
 
-print("nice " * rnd + "things.")
+print("nice " * rnd + "things.")