Fix doxygen links in log.h.

`@{link blah}` != `{@link blah}`. The latter defines a link to blah,
the former defines a custom group that is never closed. This was doing
really exciting things to devsite.

Most identifiers do not need to be explicitly linked. The two in the
struct do need to be for some reason (maybe typedef vs function, or
maybe because it's a struct, idk). I've left those two but removed all
the ones that work implicitly.

Test: staged to devsite
Bug: None
Change-Id: I9f382dab499abb27945d178e17ae8c810c619898