show: print var"ccall" correctly

[aviatesk]

No description provided.

[Keno]

Does lowering actually understand this as a keyword:

julia> var"ccall" = 1
ERROR: syntax: invalid assignment location "ccall" around REPL[2]:1
Stacktrace:
 [1] top-level scope
   @ REPL[2]:1

julia> var"ccall"(:time, Csize_t, (Ptr{Csize_t},), C_NULL)
0x0000000068994f23

I don't think there's any parse difference between ccall and var"ccall. Possibly there should be, but as long as there isn't, this seems incorrect.

[aviatesk]

Right... I hadn't noticed that. I did some investigation with Claude, but for the following reasons, I think we should close this PR for now.

---

Supporting var"ccall" and var"cglobal" would require threading metadata through the parser to distinguish symbols created via var"" syntax from bare symbols, since valid-name? currently rejects both unconditionally, and the special-case handling in julia-syntax.scm for ccall in function position relies on simple symbol equality checks that would need refactoring to handle the distinction. Given that these intrinsics are rarely needed as variable names and the implementation would require non-trivial changes to both the Scheme-based parser and lowering passes, the cost-benefit ratio doesn't justify the added complexity.