all: Rename the "NORETURN" macro to "MP_NORETURN".

This commit renames the NORETURN macro, indicating to the compiler
that a function does not return, into MP_NORETURN to maintain the same
naming convention of other similar macros.

To maintain compaitiblity with existing code NORETURN is aliased to
MP_NORETURN, but it is also deprecated for MicroPython v2.

This changeset was created using a similar process to
decf8e6a8b ("all: Remove the "STATIC"
macro and just use "static" instead."), with no documentation or python
scripts to change to reflect the new macro name.

Signed-off-by: Alessandro Gatti <a.gatti@frob.it>

py/misc.h

@@ -105,7 +105,7 @@ void *m_realloc(void *ptr, size_t new_num_bytes);
 void *m_realloc_maybe(void *ptr, size_t new_num_bytes, bool allow_move);
 void m_free(void *ptr);
 #endif
-NORETURN void m_malloc_fail(size_t num_bytes);
+MP_NORETURN void m_malloc_fail(size_t num_bytes);
 
 #if MICROPY_TRACKED_ALLOC
 // These alloc/free functions track the pointers in a linked list so the GC does not reclaim