Make public parse similar to export

[GunnarFarneback]

I expect public to parse similarly to export, but that doesn't seem to be the case.

On Julia 1.11.0-rc3 (and all other versions I have tested):

julia> begin
           export foo
       end

julia> begin
           public foo
       end
ERROR: ParseError:
# Error @ REPL[2]:2:12
begin
    public foo
#          └─┘ ── Expected `end`
Stacktrace:
 [1] top-level scope
   @ none:1

julia> :(export foo)
:(export foo)

julia> :(public foo)
ERROR: ParseError:
# Error @ REPL[4]:1:10
:(public foo)
#        └─┘ ── Expected `)`
Stacktrace:
 [1] top-level scope
   @ none:1

Is this a bug or mistaken expectations?

[pfitzseb]

public very intentionally is only a valid keyword in toplevel (module) scopes to limit breakage of existing code. export always was a keyword (importantly, for Julia 1.x), so there's no need to be extra careful with existing code.

[LilithHafner]

We may be able to improve the situation in Julia 1.13 or some-such following a deprecation. Depending on how important backwards compatibility vs consistent parsing of public/export is. Leaving this issue open to track that possibility.