Filling out the WAT inline alias syntax

(Filing this for consideration later in a polish phase before 1.0; I don't expect this is a high priority until then since it's additive and I haven't heard anyone asking for it.)

#276 pointed out that it might be nice for the inline alias syntax to be co-expressive with out-of-line aliases and, as part of what this syntax would look like, that we don't necessarily need explicit export or outer tokens to discriminate the two cases (b/c they are lexically distinct).

Thus, a complete set of inline alias syntaxes could be:

(sort 1 2)    ~> (alias outer 1 2 (sort))
(sort $C 2)   ~> (alias outer $C 2 (sort))
(sort 1 $f)   ~> (alias outer 1 $f (sort))
(sort $f)     ~> (alias outer $f (sort))
(sort $C "e") ~> (alias export $C "e" (sort))
(sort 1 "e")  ~> (alias export 1 "e" (sort))

Start by reading issue #276 and comparing the existing inline and out-of-line alias syntax. Determine how the proposed complete set of inline forms should fit the specification, and consider the work done when the syntax and its intended interpretation are agreed and documented.