libcamera: Unify Doxygen file directive prefix for formats.h

libcamera has two formats.h headers, an internal one in
include/libcamera/internal/, and a public one generated at build time.
The convention is to prefix the internal header name with
libcamera/internal/ in the Doxygen file directive, but formats.cpp only
uses internal/ as a prefix. Unify it with the rest of the code base.

Signed-off-by: L
	}
};

TEST_REGISTER(RequestBuffersTest)