Rename brace_up_array_pre -> chk_char
Prevent sub-struct initialisation inside braces

e.g.
struct A { int i; };
struct B { struct A a; };

struct A a = { ... };
struct B b = { a }; // fine
struct B b = { { a } }; // bad - initialising B::A::i with struct A
struct B b = { .a = a }; // fine
struct B b = { .a = { a } }; // bad for the same reason
Don't warn about missing braces when init-via-struct-copy