The code that handles inplace-operator to normal-binary-operator fallback
is moved in this commit from py/objtype.c to py/runtime.c, making it apply
to all types, not just user classes.
Signed-off-by: Damien George <damien@micropython.org>
So that user types can implement reverse operators and have them work with
str on the left-hand-side, eg `"a" + UserType()`.
Signed-off-by: Damien George <damien@micropython.org>
