bug#40671: [DOC] modify literal objects

[Drew Adams]

> distinguish between constant objects (which the
> program should not change) and mutable objects
> (which the program can change).

That's just not what "constant" means.  And I
suspect that your _uses_ of _not_ "mutable" will
still be for things that we really want to say
you probably _should not_ change, and not that
you _cannot_ change them.

You are once again confusing things for readers,
I think.

Something you probably _should not_ change is
not necessarily a constant.  (And the converse
isn't strong enough - you simply _cannot_ change
a constant.)

And places where you will likely say there's no
reason you _shouldn't_ change something will
likely give the impression that this is because
it is "mutable", and give the impression that
there's no reason you shouldn't change anything
that you _can_ change.  This can give the
impression  that if you _can_ change something
(the real meaning of "mutable") then there's no
reason you shouldn't change it.  That's the
wrong message.