update examples to 10.0.0

`/** */` is considered as doc comment now.
The old example just uses it as multi-line comments for print output.
Thus, I change it to `/* */` instead.

Author: weakish

pages/docs/manual/latest/api/belt/range.mdx

@@ -27,7 +27,7 @@ equivalent to `Belt.Array.(forEach(range(start, finish), action))`
 ```res example
 Belt.Range.forEach(0, 4, (i) => Js.log(i))
 
-/**
+/*
  * prints:
  *   0
  *   1