[Bug c/66298] -Wmisleading-indentation should also detect missing indentation

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66298

--- Comment #2 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
IIRC, currently the warning is checking for guards that appear to guard a
statement, but which don't; the above examples are all for guards that don't
appear to guard a statement, but do.