The informal specifications of optional-const and optional-new used to
be incomplete, and this CL adds missing parts (transformation rules for
lists and maps, and for `assignableExpression`).
This version of the documents preserves the property that no `const` is
added without immediate syntactic justification.
The alternative (where `const` is used also in other contexts where
either `const` or `new` must be added, just because we can do that)
is not specified here, that'll be another CL. The corrections done in
this CL will be needed, anyway, so I separated the two.
R=lrn@google.com
Review-Url: https://codereview.chromium.org/3005833002 .
Erik Ernst
00e98af7ef