py/compile: Remove TODO about name mangling.

This TODO is now covered by the tests/cpydiff/core_class_name_mangling.py
test.

Signed-off-by: Damien George <damien@micropython.org>

py/compile.c

@@ -41,8 +41,6 @@
 
 #if MICROPY_ENABLE_COMPILER
 
-// TODO need to mangle __attr names
-
 #define INVALID_LABEL (0xffff)
 
 typedef enum {