Minor workaround in doxygen_basic_translate_style3 test

With the "///" doxygen comment style, comments within a code block do
not get handled correctly.  Modifying the test to remove this case and
adding a note about it for future reference.

Examples/test-suite/python/doxygen_basic_translate_style3_runme.py

@@ -49,7 +49,7 @@ Warning: This may not work as expected
 
     int main() { while(true); }
 
-    // Test blank line in code block
+    int testBlankLine() {}
 }"""
 )
 comment_verifier.check(inspect.getdoc(doxygen_basic_translate_style3.function5),