misra: Fixed a crash in rule 8.2 (#3208)

Due to incorrect indentation, we return "None" instead of an empty list,
which causes the crash.

The problem was reported on the forum: https://sourceforge.net/p/cppcheck/discussion/general/thread/e146b8d779/

addons/test/misra/misra-test.c

@@ -8,6 +8,8 @@
 #include <file,.h> // 20.2
 #include "file,.h" // 20.2
 
+#include "misra-test.h"
+
 #include /*abc*/ "file.h" // no warning
 /*foo*/#include "file.h" // no warning
 #include "./file.h" // no warning

addons/test/misra/misra-test.h

@@ -1,4 +1,5 @@
 #ifndef MISRA_TEST_H
 #define MISRA_TEST_H
 struct misra_h_s { int foo; };
+bool test(char *a);
 #endif // MISRA_TEST_H