Fix warnings found by clang

There are some warnings if build python via clang:

Parser/pegen.c:820:29: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
_PyPegen_get_memo_statistics()
                            ^
                             void

Fix it to make clang happy.

Signed-off-by: Chenxi Mao <chenxi.mao@suse.com>

Author: Chenxi Mao

Parser/pegen.c

@@ -250,15 +250,15 @@ _PyPegen_fill_token(Parser *p)
 #define memo_statistics _PyRuntime.parser.memo_statistics
 
 void
-_PyPegen_clear_memo_statistics()
+_PyPegen_clear_memo_statistics(void)
 {
     for (int i = 0; i < NSTATISTICS; i++) {
         memo_statistics[i] = 0;
     }
 }
 
 PyObject *
-_PyPegen_get_memo_statistics()
+_PyPegen_get_memo_statistics(void)
 {
     PyObject *ret = PyList_New(NSTATISTICS);
     if (ret == NULL) {