Move out of misc/ and put in own folder and add the grouping to doxygen
to be able to reference the doxygen docs into RST.
Move each item into their own file to reduce clutter and to make it
less crowded in one single page.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
move misc/rb.h to sys/rb.h and
create a shim for backward-compatibility.
No functional changes to the headers.
A warning in the shim can be controlled with CONFIG_COMPAT_INCLUDES.
Related to #16539
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
