Printing of multiplication and vs. UInt16 etc.

[mcabbott]

This is a bit odd:

julia> :(2 * a)
:(2a)

julia> 2a
ERROR: UndefVarError: a not defined
Stacktrace:
 [1] top-level scope at REPL[6]:1

julia> :(0x0 * a)
:(0x00a)

julia> 0x00a == 10
true

From here: https://discourse.julialang.org/t/not-clear-what-0-01f0x-is-in-the-flux-docs/40553/4