nested comments

[backtracking]

Nested comments are accepted in Koka source code, but then are copied verbatim in C source code, resulting in errors after the first closing */. For instance, this Koka source code

/* a /* b */ fun main () 1 */
fun main() 42

results in the following syntax error:

test.h: In function ‘main’:
test.h:30:26: error: expected declaration specifiers before numeric constant
   30 | /* a /* b */ fun main () 1 */
      |                          ^

I'm using Koka version 3.1.2.